One challenge could be readjusting to the village life. After intense training in a different environment, the daily routines and social norms of Konoha might seem strange. Also, he may face jealousy from some of his peers who haven't advanced as much in their skills during his absence. Another challenge could be dealing with the new threats that Konoha might be facing, and having to prove himself all over again to the village elders that his new skills are useful for the village's protection.
It could be a rogue ninja who has been secretly building power while Naruto was away. This rogue ninja might have a vendetta against Konoha and sees Naruto's return as a challenge to his plans. So he directly confronts Naruto to prove his own strength.
Some villagers might be in awe of his new strength and abilities. They could see him as a great protector now. However, there may also be those who are still skeptical or even afraid because of his past as the container of the Nine - Tails. His friends would likely be overjoyed to see him back and eager to train with him or learn from him.
Well, it could be that Naruto has found a way to tap into some ancient and forgotten power source during his time away. So when he comes back to Konoha, he's not only physically stronger but also has a deeper understanding of chakra and how to manipulate it. He might start by showing off his new skills to his old friends like Sasuke and Sakura. And then, he uses his strength to improve Konoha's defenses, such as creating new barriers around the village using his enhanced chakra control.
Well, it could be about Naruto coming back to Konoha with some new powers related to the golden fox. Maybe he uses these powers to protect the village from a new threat.
Well, Naruto's friends and comrades from his past adventures are likely to be in it. But also, there could be some spiritual or mythical characters related to the concept of the golden fox. For example, there might be an old sage who knows the secrets of the golden fox and can guide Naruto on how to use its power properly. There could also be other villages' representatives who come to Konoha to see this 'Naruto with the golden fox' phenomenon and see if it poses a threat or an opportunity for their own villages.
Well, perhaps Naruto comes back with some super - strong new jutsu that he learned during his absence. He might show off his new power to his old friends and foes alike, leaving everyone in awe.
Perhaps it's an old enemy who has somehow managed to come back stronger. Maybe someone from Orochimaru's old experiments that went wrong, but instead of dying, they gained some dark and powerful abilities. They see Naruto's return as a threat to their plans of world domination, so they target Konoha first. They might be able to control dark chakra in a way that no one has seen before, and use it to create chaos and destruction. They could also have some minions who are equally as powerful and loyal to them, making them a formidable foe for Naruto and Konoha.
One possible fanfiction could involve Itachi returning from the dead in some way. He decides to train Naruto to help him master new skills. Itachi might teach Naruto some of the more advanced Uchiha techniques, like advanced fire - style jutsu or the sharingan - related skills he has. Naruto, with his own vast chakra reserves and unique abilities, would then combine these new teachings with his own Rasengan - based attacks. This could lead to some really cool battle scenes in the fanfiction where Naruto surprises his enemies with new moves.
One possible reason could be fear. Naruto has the Nine - Tails within him, and some in Konoha might be too afraid of its power getting out of control. They may not fully trust Naruto to keep it in check.