In these fanfics, Nagato may help Naruto on an ideological level. Nagato once believed in a very different way of achieving peace. By sharing his journey and how he came to realize the flaws in his thinking, he can guide Naruto in his pursuit of true peace. Nagato could also use his influence over the Akatsuki remnants to prevent them from causing more chaos, which in turn helps Naruto in his mission to protect the ninja world.
In some fanfictions, Naruto and Nagato might be related through their shared experiences with the ninja world. They both faced great tragedies. Naruto could be seen as a successor to Nagato's ideals in a way. Nagato once wanted peace through force, but Naruto shows that peace can be achieved through understanding and forgiveness.
One possibility is that there was some sort of spiritual or chakra - based connection between Naruto and Nagato. Nagato, being the possessor of the Rinnegan, recognized Naruto's strong will and the fact that he was on a path to change the ninja world for the better. Through this connection, Nagato was able to transfer the power of the Rinnegan to Naruto. It could also be related to the nature of the Sage of Six Paths' power that was somehow involved in this transfer, as both Naruto and Nagato were related to the Sage in different ways.
In some fanfiction concepts, there could be a spiritual or mental connection established between Naruto and Nagato. Since Naruto has this unique ability to understand and connect with people on a deep level. Through this connection, Nagato might pass on the power of the Rinnegan to Naruto. It could be like a transfer of not just the physical power but also the knowledge and understanding that comes with the Rinnegan.
In this fanfiction, perhaps Naruto confronts Kushina about the secrets she kept from him. For example, if there were things she knew about his powers or his destiny that she didn't share before her death. He could be feeling betrayed and wants answers.
He could be more light - hearted. Instead of being burdened by his past immediately, he might start off with a more positive outlook. For instance, he could be curious about the new world around him and approach things with a sense of wonder.
Naruto's reaction could be complex. Since he has his own feelings for Sakura, this situation could stir up a lot inside him. He might initially be a bit hesitant in how to approach her because he doesn't want to overstep any boundaries. But in the end, his natural instinct to help a friend would take over. He would listen attentively to Sakura, his eyes full of determination to make her feel better, and use his own unique way of thinking to give her advice or just be a shoulder to cry on.
Maybe Nagato had a relationship with an Uzumaki woman before he became fully involved in the Akatsuki. This woman could have given birth to Naruto but for some reason, Naruto was separated from Nagato at a young age. It could be due to the chaos and danger that Nagato was getting into with his plans for the Akatsuki.
Yes, there are some interesting 'Naruto is Nagato' fanfictions. You can find them on popular fanfiction websites like FanFiction.net or Archive of Our Own. Some of these fanfictions explore unique storylines where Naruto has a connection or even an identity swap with Nagato, which can be really fascinating.
One great 'Naruto Nagato and Konan Fanfiction' is 'The Redemption of Nagato'. It shows Nagato's journey towards finding a new path after his actions in the war. Konan is also beautifully portrayed as his loyal friend, always by his side, guiding him to a more positive way of life.