The relationships of Nala.
Romance
Simba
As cubs, Nala and Simba were best friends and would go on adventures together (including the visit to The Elephant Graveyard). Both cubs were not pleased to learn that they were betrothed to each other, claiming that they could not marry because they were friends. After escaping Zazu, she and Simba argue over whose idea it was and get into a play fight. Nala easily beat Simba after he pounced her by flipping and pinning him, and did so once again when he tried pouncing her a second time, teasing him "pinned ya again." While the two were later being chased by the hyenas, Nala was nearly killed by Shenzi, but Simba saved her by scratching Shenzi. Nala, along with the rest of the pride, was devastated when Scar told them that Simba, along with Mufasa, had perished in a wildebeest stampede.
Years later, Nala gets into a fight with a young lion, whom she pins down. The lion recognizes this move and says Nala's name and says that he is Simba, which makes Nala overjoyed that her friend was alive. Eventually, the two friends became lovers, something they thought wouldn't happen when they were cubs. After the two tumbles down a hill together, Simba finally pins Nala, and she rewards him with a surprise lick on the cheek and they nuzzle each other lovingly. Nala joins Simba in battling Scar and the hyenas, after learning that Scar was responsible for Mufasa's death and had blamed Simba for it.
In the second film The Lion King II: Simba's Pride, Nala, unlike Simba, isn't overprotective of their daughter Kiara and is more accepting towards Kovu, whom Simba distrusts due to him being Scar's heir. Nala expressed shock when Simba decided to banish Kovu for supposedly being involved in the Outsiders ambush and did not let him explain himself. She did express happiness when Simba later had a change of heart and allowed Kovu and the Outsiders to rejoin the pride.
In The Lion Guard: Return of the Roar, Nala accepts her and Simba's son Kion's destiny to be leader of The Lion Guard whereas Simba believed that their son wasn't ready for that responsibility as he was cub. After Kion and The Lion Guard save Kiara from a stampede and defeats Janja and his clan (who started the stampede), Nala and Simba express pride in their son.
Family
Sarafina
Nala appears to have a close relationship with her mother, Sarafina. She was seen resting in her mother's paws at the start of the film and willingly allowed her mother to bathe her, whilst Simba struggled to escape Sarabi's grasp.
Kiara
Nala has a loving mother-daughter relationship with her daughter. Unlike Simba, she doesn't act overprotective of her and believes that their daughter would be fine on her own.
During Kiara's childhood, Nala would help her in tracking gazelles in preparation for her first hunt.
When Kiara becomes an adolescent and prepares for her first hunt, Nala assures her that she will do just fine. Nala is relived when she and Simba find Kiara safe from the fire in The Pride Lands and when Simba is reluctant to let Kiara's childhood friend and saviour Kovu into the pride and Nala points out to him that he owes Kovu Kiara's life.
Nala along with Kiara is shocked when Simba exiles Kovu for supposedly being part of Zira's ambush. After Kiara and Kovu stop the battle, Nala watches in horror as Kiara and Zira fall down a cliffside. After Simba is able to get Kiara back up the cliff, a relived Nala hugs her daughter.
Nala then watches proudly as Kiara marries Kovu and roars along with her, Simba and Kovu.
Kion
Nala appears to have a close mother-son relationship with her son Kion.
Unlike Simba, Nala accepted that Kion was ready to lead The Lion Guard and encouraged Simba to listen to Rafiki (who said that Kion was ready). Also unlike Simba, Nala supported Kion's choice to have his friends make up the guard instead of other lions. After Kion and The Lion Guard save Kiara and defeat Janja and his clan, Nala expresses pride in her son. Kion cares about her deeply and becomes concerned about her whenever she's in danger as seen in Never Roar Again.
When Kion is blemished with the Mark of Evil, Nala is deeply concerned for her son and is utterly horrified when Rafiki reveals that there is no cure for him in the Pride Lands. After Kion departs for the Tree of Life, Nala continues to miss him many months later and is overjoyed when she not only sees him return but when he becomes King of the Tree of Life.
Mufasa
While they were not shown interacting, Nala has a great deal of respect for Mufasa. He saved her and Simba from the hyenas when she was a cub; his strength and bravery, vastly surpassing Simba's, greatly impressing her. Nala was saddened to learn that Mufasa had died. With the Pride Lands having become a barren wasteland under his brother Scar's reign, Nala states it's good someone is emulating the wise and sensible individual Mufasa was when Simba, refusing to return to reclaim his birthright, states her disappointment in him reminds him of his father. She got mad at Scar after finding out that it was he that killed Mufasa. After Nala marries Simba, Mufasa posthumously becomes her father-in-law.
Sarabi
Nala knew Sarabi since she was a cub because she was friends with Simba. Nala helps Sarabi and Simba fight Scar. After Nala marries Simba, she gains Sarabi as her mother-in-law.
Scar
Nala hates Scar for how he let the hyenas invade the Pride Lands and disrupt the natural balance by the Circle of Life when he took the throne. After Simba fled the Pride Lands following his father's death, she believed that Simba died alongside his father in the wildebeest stampede. However, Nala discovered that Simba survived when they were adults and urged him to return to the Pride Lands and claim his rightful place as king. She stood by Simba's side when he fought Scar after finding out that Scar was behind the murder of Mufasa. With her marriage to Simba, Scar became Nala’s posthumous uncle-in-law, a relation that, compared to either Mufasa or Sarabi, was not a positive one given his betrayal against his family who effectively disowned him.
In a deleted scene and the musical Scar wanted Nala as his mate and Queen.
Kovu
Unlike Simba at first, Nala accepted Kovu into the Pridelanders after he saved Kiara from the fire. She later encouraged Simba to give Kovu a chance. Nala was shocked and saddened when Simba banished Kovu from The Pride Lands for supposedly being involved with Zira's ambush of him. After Simba apologies to Kovu and allows him and the Outsiders to rejoin the pride, Nala watches on happily as Kovu marries Kiara, thus gaining him as her son-in-law.
Rani
Rani is Nala's daughter-in-law after her marriage to Kion. She attended their wedding and Kion's coronation/crowning him as King of the Tree of Life beside Rani as Queen. Nala delighted to have Rani as her daughter-in-law and will love and cherish her as much as she dose Kion and Kiara.
Friends
Timon and Pumbaa
Nala first came across Timon and Pumbaa as an adult, when she attempted to hunt Pumbaa, only to fight against an adult Simba. When Nala discovered that she was fighting Simba, after years of thinking he was dead, she was overjoyed and was soon introduced to Timon and Pumbaa, forsaking her original plan of eating them. While Pumbaa was more polite and accepting towards Nala, Timon was confused and skeptical about meeting her, scoffing about her claim that Simba is the king. Despite this, she remained polite towards them and gently asked them to give her and Simba some privacy. Later on, when Nala finds out that Simba has returned to Pride Rock, she informs Timon and Pumbaa about it and together, they join Simba in the battle for Pride Rock, working together to defeat the hyenas. Since then, Nala has come to see Timon and Pumbaa as good friends and helpers and vice versa.
Zazu
As a cub, had the habit of teasing Zazu and ditching him whenever Simba was asked by Sarabi to accompany him and her, on their adventures, much to Zazu's dismay. As an adult and queen after Simba ascends as king, Nala became more respectful and professional with Zazu, and as her Royal Advisor, who reports everything to her and Simba. In general, the two are good friends.
Rafiki
Nala did not meet Rafiki until after he shows up in the jungle and tells her, Timon and Pumbaa that Simba returned to the Pride Lands to challenge Scar. When she finds out that Scar killed Mufasa, Nala helps Rafiki and Simba fight Scar.
Rafiki is a close friend of the royal family who always helps them out if they are sick or hurt. From what we have seen so far, the two seem to be good friends, with Nala having much trust in Rafiki as their Royal Mjuzi.
Enemies
Shenzi, Banzai, and Ed
She and Simba dislike the hyenas the way they hate Scar. The first time Nala and Simba met the trio, they were just cubs, when Scar tempted Simba into going to the elephant graveyard. After Mufasa's and Simba's (presumed) death, Sarafina is seen comforting Nala, when the hyena clan invade the Pride Lands on Scar's orders, and in the future the hyenas decimated the Pride Lands due to over-hunting
Nala, later on helped Simba in defeating Scar and his tyranny, by fighting hyenas with the help of Timon, Pumbaa, Rafiki, Zazu, Sarabi, Sarafina and the other lionesses.
Zira
Though they are only seen briefly addressing each other in The Lion King II: Simba's Pride, Nala did not have a good relationship with Zira due to the latter's loyalty to Scar. Nala alongside Simba, Timon, Pumbaa and two lionesses, faced against Zira in defense of Kiara.
Years later, Nala and her pride faced against Zira and the Outsiders, which ended in Zira's death and the Outsiders reforming.