In a more creative fanfic, an ancient ninja who was the originator of the Chidori technique could appear. This ninja could be brought back to life through some sort of magic or jutsu. He sees Naruto's pure heart and decides to pass on the Chidori knowledge to him, believing Naruto will use it for good.
Maybe Sasuke teaches him the Chidori in a moment of camaraderie. And for the Rasengan, it could be an older and wiser Naruto from the future who travels back in time to teach his younger self.
In a fanfic where Naruto knows the Chidori, it could change the power dynamics in battles significantly. Naruto's already vast chakra reserves combined with the piercing and fast - acting nature of the Chidori would make him an even more formidable opponent. He could use it in close - quarter combat situations, perhaps integrating it with his Shadow Clone Jutsu in creative ways. For example, he could have clones perform the Chidori from different angles, catching his enemies off - guard.
In fanfiction, Naruto creating Chidori could be possible through some creative plot devices. Maybe he was taught by Sasuke in an alternate universe where they teamed up earlier. Or perhaps he discovered a scroll that had the knowledge of Chidori and was able to learn it on his own with his determination and quick - learning ability.
In many Naruto fanfictions, the Chidori - Rasengan combo is often portrayed as an extremely powerful and unique move. It combines the piercing nature of the Chidori with the rotational and explosive force of the Rasengan. Some fanfictions might have Naruto or Sasuke (or both in some cases) creating this combo during a crucial battle against a powerful enemy, like a new Akatsuki member or a rogue ninja from another village. This combo is usually described in great detail, with the lightning - chakra of the Chidori surrounding and enhancing the Rasengan, making it not only more destructive but also having an added effect like paralysis due to the electricity.
Sasuke could be Naruto's teacher. Since Sasuke is a master of the Chidori, he might decide to teach Naruto as a way to make Naruto a more formidable ally. They have a complex relationship, and this could be a way to strengthen their bond.
In the fanfic, Naruto could use the Chidori to save his friends who are trapped by an enemy's powerful jutsu. Since the Chidori is a very fast - moving and piercing attack, he could break through the barriers set up by the enemy. He might also face some internal struggle as using the Chidori goes against his normal style of ninjutsu.
One possible scenario could be that Naruto learns the Chidori from Sasuke in a moment of truce. Sasuke, realizing Naruto's determination to become stronger, decides to teach him this powerful jutsu. Another could be that Naruto discovers a scroll that contains the secrets of the Chidori and through his own hard work and study, he manages to master it. Or perhaps, a new character appears who has knowledge of the Chidori and trains Naruto in it as part of a greater plan to defeat a common enemy.
One possible plot could be that Naruto discovers the Chidori technique while training in a secret area. Maybe he stumbles upon some old scrolls left by Kakashi. He then has to train hard to master it, facing difficulties like controlling the lightning chakra. As he progresses, he combines it with his own unique Rasengan, creating a new and powerful jutsu.
One consequence could be a shift in his relationships. Sasuke might be both impressed and a bit threatened. Their rivalry could take on a new dimension as Naruto now has a jutsu similar to Sasuke's signature move. Also, the village might view Naruto in a new light, as he's mastered a foreign - seeming jutsu. It could make him seem more versatile and dangerous to enemies.