A great plot could be that there is a threat that is causing chaos in both the Naruto world and the Big Hero 6 world simultaneously. The two groups meet while investigating the source of this threat. Naruto, with his determination and strong will, would inspire Hiro to be more confident in himself. They could combine their unique abilities. For example, Naruto could use his shadow clone jutsu to help Big Hero 6 in a large - scale battle, while the technology of Big Hero 6, like Fred's suit, could be used to give Naruto an edge against certain enemies in his own world.
One possible plot could be that the Big Hero 6 team is working on a new project in San Fransokyo when a strange series of crimes start to occur. These crimes seem to involve some sort of advanced technology that is out of this world. Spider - Man, who is on a school trip to San Fransokyo, senses that something is wrong. He starts to investigate on his own. Eventually, he crosses paths with the Big Hero 6. At first, there's some misunderstanding and a bit of a scuffle as they don't know each other. But when they realize they are after the same bad guys, they team up. Hiro figures out a way to integrate some of Spider - Man's web - slinging tech into Baymax's systems for a new attack mode, and together they take on the villain who is trying to use the stolen tech to create a portal to another dimension.
A plot might involve a villain who has stolen some of Syndrome's old tech and is using it in combination with the technology from Big Hero 6's universe. The Incredibles and Big Hero 6 team up to track down this villain. Frozone could use his ice powers to freeze some of the overheating tech created by the combined bad - guy tech. Honey Lemon's chemical - based gadgets could be used to counteract some of the effects of Syndrome's old inventions. And Jack - Jack, with his multiple powers, could provide some unexpected solutions and comedic relief during their adventure.
Perhaps there's a glitch in Baymax's system that causes him to project Riley's emotions as holograms. Hiro is confused at first but then realizes that these emotions are from someone else. They track the source of the connection and end up in Riley's mind. There, they find that the emotions are in chaos because of the sudden link to Baymax. The Big Hero 6 characters use their skills to help the Inside Out characters restore order. Hiro and Baymax help Joy understand how to better manage the positive emotions while the rest of the team helps the other emotions like Sadness not feel so left out or misunderstood.
In a 'Big Hero 6' and 'Inside Out' crossover fanfiction, perhaps Riley visits San Fransokyo. During her visit, she witnesses an accident that Big Hero 6 is responding to. The chaos and destruction make Sadness start to surface strongly in her. Baymax senses her distress and tries to help her. This leads to the team inviting Riley to their lab to cheer her up. Inside their lab, the emotions are fascinated by all the high - tech gadgets and start interacting with them, causing some comical and unexpected situations as they blend the two very different worlds of technology and emotions.
Maybe in this fanfiction, the gamer aspect brings in a system of quests to the Naruto world. Naruto has to complete various quests around the Hidden Leaf Village, like helping villagers with their daily problems or finding rare items. These quests could reward him with new jutsu or power - ups. It would be like he's living in a real - life RPG, which would add a whole new layer of adventure to the Naruto universe.
One possible plot could be that Naruto and his friends from the Naruto universe are suddenly transported to the Destiny universe. They could be mistaken for new Guardians at the Tower. Naruto's chakra abilities might be misinterpreted as a new form of Light power. They then have to team up with Destiny's Guardians to fight against a common enemy that threatens both universes, like a powerful Darkness entity that has somehow found a way to cross over from Naruto's world where the Akatsuki's actions have weakened the barriers between worlds.
One interesting plot could be that Ichigo and Naruto are brought together in a strange alternate dimension. In this dimension, they have to team up to fight a new common enemy that has powers combining the Hollow and the Nine - Tails. They start off not understanding each other's abilities but gradually learn and combine their powers in unique ways to defeat the enemy.
A plot might involve Batman investigating strange energy readings in Gotham that turn out to be related to Naruto's world. Naruto arrives in Gotham following a villain from his own world who is after some powerful technology in Batman's possession. Naruto and Batman start off at odds but as they learn more about each other's strengths and motives, they form an alliance. Naruto teaches Batman about chakra and the ninja way, while Batman shows Naruto how to use stealth and technology in a more urban environment.
One possible plot could be that Naruto, through some strange space - time rift, ends up in Kaguya's era. He could then team up with her against a common enemy that threatens both their worlds. Naruto's unique jutsu and his never - give - up attitude might inspire Kaguya, and together they could create new and powerful techniques.
One possible plot could be Naruto and his friends being summoned to the world of For Honor. Naruto, with his ninja skills, could team up with the samurai and Vikings in For Honor. He might teach them some of his unique jutsu, like the Shadow Clone Jutsu to create diversions in battles. And in return, he could learn the combat styles of the For Honor warriors. They could then face a common enemy that threatens both the ninja world and the For Honor world.