Well, for starters, Naruto's physical appearance might be different as he would inherit some Uchiha traits. In terms of his personality, Mikoto could instill different values in him. She was a loving and protective mother in the original story. So Naruto might be more in touch with his emotions. Story - wise, the Uchiha massacre would likely have a different impact on him. He might be more involved in seeking justice for the Uchiha, and his path to becoming Hokage could be intertwined with resolving the Uchiha issues. Additionally, the relationship between Naruto and Itachi would be very strange. Itachi might see Naruto in a different light, knowing he has a connection to Mikoto.
He might be more reserved. Since Mikoto was known for her grace and elegance, Naruto could adopt some of those traits. He may not be as loud or brash as in the original series.
Naruto could be more empathetic towards the Uchiha's cause. Since Mikoto is his mother figure, he would be exposed to the Uchiha's history and their grievances from a young age. This would make him more understanding of Sasuke's later actions and more likely to try and find a peaceful solution for the Uchiha's problems.
I'm not certain if there is a specific fanfiction with Mikoto as Naruto's mother. But it's not an unlikely idea in the realm of fanfiction. Writers might be attracted to this concept because it would create a whole new dynamic. It could change Naruto's relationship with Sasuke, for instance. Since Mikoto was Sasuke's mother in the original story, having her be Naruto's mother as well would create a very different bond between the two main characters.
He'd be more in - touch with his Uchiha side. So, he might be more brooding at times. His appearance could also be different, maybe having more Uchiha - like features. His approach to problems would likely change too. Instead of just charging in head - first all the time, he might be more calculating like the Uchiha are known to be.
Naruto might be more confident from the start. Since he's the son of two respected shinobi, he could have a different self - image compared to canon Naruto. He might not have the same insecurities about being an orphan or not being good enough.
In such a fanfiction, Mikoto would likely be very protective of Naruto. As a godmother, she would probably be involved in his upbringing, teaching him things about the ninja world, and maybe even some Uchiha clan secrets if she thought it was necessary for his growth.
Naruto would likely be more confident from the start. Since he has the combined blood of Minato and Mikoto, he might not have the same insecurities as in the original story. He would probably be more aware of his potential and be more self - assured in his abilities.
Well, in this kind of fanfiction, Naruto might grow up with a different kind of family environment. He could be influenced by the Uchiha clan's traditions and values. Maybe he would learn some Uchiha - specific jutsu earlier. And he would probably have a closer relationship with Sasuke from the start as they would be like brothers in a sense.
Naruto's relationships with others would be different too. His friends might view him with a mix of awe and caution because of his relation to Kaguya. This could lead to some interesting dynamics, like Sasuke being more suspicious of Naruto at first. But as Naruto grows and shows that he is not like Kaguya in her more villainous aspects, he could earn back their trust in a more complex and character - building way.
Naruto's character would likely become more confident. With a family structure provided by Mikoto, he would feel more secure. He might also become more mature as he is exposed to the Uchiha way of life. For example, he could learn discipline and patience more quickly. His understanding of the ninja world would expand as he learns from Mikoto about different clans and their relationships.