Naruto would win. He has a lot of experience fighting powerful opponents and has developed many powerful jutsu over time. He also has the willpower and the ability to adapt in battle. Shukaku is strong, but Naruto's intelligence and his ability to think on his feet would give him the edge.
A plot might involve Shukaku being controlled by an evil force and Naruto has to fight it to save the village. Naruto starts by trying to reason with Shukaku, but when that fails, he has no choice but to engage in a fierce battle. He might call upon the help of his friends like Sasuke or Sakura at some point to create a strategy to defeat Shukaku.
The other Jinchuurikis could be potential allies. They understand the struggles and the power that comes with having a tailed beast inside them. For example, Killer Bee, who has a good relationship with his tailed beast, could share his insights on how to better co - exist with Shukaku. Tsunade might also be an ally, as she is a powerful Hokage who could offer protection and resources to the Jinchuuriki.
I would recommend 'Naruto and Shukaku: A New Alliance'. In this fanfiction, it focuses on a scenario where Naruto and Shukaku have to team up against a new, powerful enemy. It has a lot of action scenes and also some really interesting character development for both of them.
Good fanfiction in this regard also pays attention to the lore of the Naruto universe. It should be consistent with the rules about chakra, jinchuriki, and the world - building already established in the original series. If it just ignores all these elements, it won't feel like a proper 'naruto and shukaku' story.
One interesting Naruto Shukaku fanfiction could be about Shukaku's backstory before being sealed into Gaara. It might explore how it lived in the desert and its interactions with other beings there.
Obviously Naruto would be the main character. Shukaku itself or a representation of Shukaku's spirit could be there. Also, characters like Iruka sensei would still be around. His friends like Sasuke and Sakura would play important roles as they react to Naruto's new situation.
Well, it could be about Naruto having the powers of Shukaku in addition to his own. Maybe he has to learn to control this new power source and face new enemies who are after his unique abilities.
One interesting storyline could be about the relationship between the Shukaku and Naruto evolving in a unique way. For example, the Shukaku might teach Naruto some ancient and powerful jutsu that was once known only to the tailed beasts. This could give Naruto an edge in battles and also deepen their bond.
You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own (AO3). These platforms have a wide range of Naruto - related fanfictions, including those about Shukaku.