Yes, there are likely to be such fanfictions. In the Naruto series, Sakura can be quite assertive and strong - willed. Her temper and skills could potentially be a source of intimidation for Naruto in the creative interpretations of fanfiction writers.
In many Naruto fanfictions, Naruto might have developed some new and unique abilities that the Kyuubi has no defense against. This could make the Kyuubi, which is used to being a dominant and feared force, feel vulnerable. For example, if Naruto has the power to nullify the Kyuubi's chakra or to manipulate it in a way that goes against the Kyuubi's will, it would be a cause for fear.
I'm sorry, I can't directly recommend a specific 'Naruto Scared of Sakura' fanfiction. But you can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own. Use the keywords 'Naruto scared of Sakura' in the search bar, and you should be able to find relevant stories if they exist.
Maybe it's the high expectations that Naruto has for Boruto. Naruto is a hero, and he might unknowingly put a lot of pressure on Boruto to follow in his footsteps. Boruto could be scared of not being able to meet those expectations.
They could start by having an honest conversation. Naruto could sit down with Boruto and just listen to his fears without judgment. This would be a first step in building a better relationship.
Maybe it's because Nico has some complex and often dark or angsty aspects to his character in the source material. Fanfiction might explore these in extreme ways that can be disturbing to some readers.
Perhaps Jason has his own ideas and interpretations of Percy, and the fanfiction goes against those. Fanfictions are often a creative exploration by different authors, and not all of them might align with Jason's view of Percy. He might be scared that these fan - made stories could influence how others see Percy in a way he doesn't like.
Well, in some fanfictions, Bella might be scared of Edward because of his vampiric nature. His superhuman strength and speed could be intimidating. Also, the unpredictability of his actions as a vampire who is constantly fighting his bloodlust could make Bella feel scared.
Maybe Aziraphale is scared when a powerful otherworldly entity shows up that he thinks might harm Crowley. So he tries to protect Crowley in his own bumbling way. Crowley, in turn, is both amused and touched. He then shows Aziraphale that he can handle himself just fine, but also thanks Aziraphale for his concern. They end up having a little adventure trying to figure out what this new entity wants.
I think it's because Nico is a character with a lot of depth. Fanfiction might delve too deep into his psyche and expose some very raw and disturbing aspects that people aren't prepared for. It could also be that the way some fanfiction writers portray his relationships, especially the more controversial ones, makes people scared to engage with it.