Yes, there might be. The world of fanfiction is vast, and with the popularity of both Naruto and Kaido from different fictional universes, it's not unlikely that someone has created a crossover fanfiction where Naruto has some sort of connection to Kaido. You can search on popular fanfiction websites to find out.
If Naruto arrives at Marineford, it would be a chaotic and interesting scenario. Naruto's powerful jutsu like Rasengan and his ability to summon toads could change the balance of power. He might try to stop the fighting between the pirates and the marines, seeing the senseless destruction. His sense of justice and never - give - up attitude could inspire some of the characters there.
In 'luffy vs kaido fanfiction', Luffy's growth and new abilities are often explored. He might develop new forms of his Gear powers to face Kaido. Kaido, being extremely powerful, forces Luffy to push his limits. Fanfictions may also focus on the intense battle scenes, with detailed descriptions of their attacks and counter - attacks.