One possible plot could be that Naruto is somehow given Broly's power. He then has to deal with the new - found, almost uncontrollable power within him while still trying to protect his village. His friends might be scared of him at first because of the sudden change, but Naruto has to prove that he's still the same person inside.
A possible plot could be that an ancient jutsu in the Naruto world goes wrong and accidentally links Naruto to Broly from another dimension. As a result, Naruto starts to exhibit Broly's characteristics like his super strength and a temperamental nature. The story could be about Naruto's journey to separate himself from Broly's influence. He would face many challenges, not only from his own village which is now wary of him, but also from enemies who see this new - powered Naruto as a greater threat than before. He would have to learn to master these new powers and use them for good, all while trying to break the link with Broly.