In some fanfictions with this theme, it could be part of a genjutsu (illusion). Naruto believes he's being burned alive while in reality, it's a mental attack. This would be a really interesting plot as Naruto has to break free from the illusion not only physically but also mentally. He could draw on his past experiences of breaking genjutsu and his strong willpower to overcome this false burning alive scenario.
One possible plotline could be that Naruto is caught in a powerful enemy's fire - based jutsu during a battle. Maybe the enemy has some vendetta against him and wants to see him suffer. Another could be that Naruto sacrifices himself by jumping into a burning building to save civilians. He might then struggle to survive the intense heat and his injuries.
One possible plotline could be that Kushina's survival changes Naruto's upbringing completely. Instead of being an orphan, he grows up with a loving mother. This could lead to him being more confident and less of an outcast in the village at a young age. He might also learn about the Uzumaki clan's secrets earlier from his mother, which could make him a more formidable ninja even faster.
One possible reason could be a powerful enemy's fire - based jutsu. For example, if Naruto is facing a skilled fire - style user like Sasuke during a battle gone wrong, Sasuke's powerful fire techniques might accidentally burn Naruto.
Well, one plotline could be that Lily uses her influence to change the way Hogwarts is run. Since she was a brilliant witch, she might introduce new spells and teaching methods. For example, she could start a special class for students to learn advanced defensive magic earlier.
One possible plotline could be that Minato and Kushina raise Naruto as a normal child in Konoha. Naruto would grow up with their love and guidance, which would significantly change his personality. He might be more confident from the start and not have that intense need to prove himself. Also, Minato could train Naruto personally, and Naruto might inherit his father's skills much earlier, leading to different adventures and battles in the ninja world.
One possible plotline could be that Naruto is banished due to false accusations of endangering the village, despite his parents being alive. His parents, Minato and Kushina, might be powerless to stop the decision because of some political intrigue within the village. Naruto then has to find his own way in the outside world, facing new enemies and making unexpected allies.
One common plotline is the resurrection of dead characters. If Naruto is dead in the fanfiction, there could be a quest to bring him back. Another is alternate timelines where Naruto's life - or death - changes the course of the entire ninja world. For instance, if he dies early, the Akatsuki might achieve their goals more easily.
Show the reactions of his friends. If Naruto is burning alive, how do Sasuke, Sakura, and the others respond? Their desperation, their anger at not being able to save him easily can really tug at the heartstrings. You could also include flashbacks of their times together, making the loss seem more real and tragic.
It's hard to say exactly as this is a very unusual concept for Naruto fanfiction. But perhaps it could involve a character having some sort of medical condition that causes incontinence and how they deal with it while still being a ninja. Maybe they have to hide it from their teammates to avoid being seen as weak.
One interesting plotline could be that Naruto is a reincarnation of a powerful Witcher in the Naruto world. He has latent Witcher powers that start to awaken as he grows up. As he discovers his powers, he also uncovers a conspiracy that links the Ninja world and the Witcher world. He has to use his Ninja skills and his emerging Witcher skills to solve the mystery and save both worlds from a great danger. This would involve a lot of character development, as Naruto has to balance his two identities and figure out how to use his powers effectively in different situations.
One plotline could be that Naruto is chosen by Poseidon to be his champion in the human world. He is given special powers to protect the seas and their secrets from those who would misuse them. Naruto, with his determination, uses these new powers to fight off evil forces that are threatening the ocean's balance.