He might initially be in shock. Naruto, being the strong - willed character he is, would probably first try to understand why everyone has turned against him. He could start by seeking answers from those closest to him before he decides on his next course of action, like whether to fight back or try to win them back.
Well, Sasuke could be one of the main characters involved. Since he has a complex relationship with Naruto, he might play a role in the betrayal, either as a part of the group that betrays Naruto or as someone who is conflicted about the situation. Sakura could also be involved. She has her own opinions and relationships within the Naruto universe, and she may be part of the group that turns against Naruto for some reason.
Well, if Naruto is godlike and betrayed by everyone in a fanfic, it could start with the villagers' fear of his newfound power. They might think he's a threat and turn on him. Naruto, being so powerful, could initially be in disbelief. But as the betrayal sinks in, he might decide to leave the Hidden Leaf. He could then wander the world, trying to figure out his place in it while also being cautious of those who might want to take advantage of his power or finish him off.
In such a fanfic, Naruto might become extremely bitter. He could lose his positive attitude and turn against the village that once shunned him. Maybe he would seek power elsewhere, perhaps from darker sources.
It could be the very villagers who once looked up to Naruto. Their betrayal could turn them into antagonists as they might try to further harm Naruto to protect their own interests.
In such a fanfic, the plot might start with Naruto's friends gradually turning against him due to false rumors spread by a hidden enemy. They could start to exclude him from missions and isolate him within the village. For example, Sasuke might believe the lies and challenge Naruto, thinking he has changed for the worse. This would lead to a series of battles where Naruto has to fight not only his former friends but also his own feelings of betrayal and confusion.
One possible scenario could be that Naruto's girlfriend betrays him because she is jealous of his godlike powers. Maybe she feels overshadowed and in a moment of weakness, she aligns herself with Naruto's enemies. It could lead to a great internal conflict for Naruto, having to face not only external threats but also the pain of betrayal from someone he loved.
One idea could be that in the fanfiction, Hinata is under the influence of a powerful genjutsu. This genjutsu makes her see Naruto as a threat to the Hidden Leaf village. So, she betrays him to protect the village in her distorted view. It could lead to a lot of inner conflict for Hinata once she realizes the truth and Naruto having to deal with the pain of her betrayal.