One idea could be that Naruto is somehow transported to the Marvel universe and meets Doctor Strange. Doctor Strange could sense Naruto's unique chakra and be intrigued. He might offer to train Naruto in new forms of magic that are similar to his jutsu. Naruto, in turn, could show Doctor Strange some of his ninja skills, like his shadow clone jutsu which could be useful in combat situations in the Marvel world.
If Naruto and Doctor Strange fought, it would be an interesting match. Naruto is extremely powerful with his chakra and various jutsu. However, Doctor Strange has the power of the mystic arts. Doctor Strange could potentially use his magic to trap Naruto in another dimension or create illusions to confuse him. But Naruto's speed and his ability to sense danger might allow him to avoid some of Doctor Strange's attacks and get close enough to land a powerful punch or use a jutsu like Rasengan.
One possible plot could be that Naruto discovers the world of Doctor Strange through some kind of interdimensional rift. He is intrigued by Strange's magic and decides to learn it. Naruto, with his already existing chakra abilities, might find a unique way to blend his ninja skills with the magic of Doctor Strange. For example, he could use his shadow clone jutsu in new ways, like sending clones into different magical dimensions to gather information or power sources.
Well, Naruto might learn some really cool magic stuff from Doctor Strange. He could use magic instead of chakra in some ways. Maybe he'd have a different fighting style, like using magic seals instead of hand signs for jutsu.
Sure, Doctor Strange has been part of the Avengers in the comic universe. His magical expertise added a unique dimension to the team's capabilities and strategies.
I wouldn't say Doctor Strange comics are niche. They offer unique storylines and magical elements that attract a specific group of fans. But they haven't achieved the same level of mass popularity as the most well-known comic franchises.