Naruto has the power of the Nine - Tails, which is a huge source of chakra. Bishamon has her own reservoir of divine power. In a fanfiction, they could combine their powers by having Naruto transfer some of his chakra to Bishamon, who then uses it to supercharge her attacks. Or vice versa, Bishamon could bestow some of her divine essence on Naruto, allowing him to access new forms or abilities that are a blend of both ninja and divine powers.
Sure, the Noragami manga is completed. It was a great ride with an ending that wrapped up the plot nicely. If you haven't read it yet, it's worth giving a go.
Noragami is about a minor god named Yato. He wants to have a grand shrine and a lot of followers. He meets a girl named Hiyori who can partly leave her body due to an accident. They get involved in various supernatural events and battles against other spirits and gods. Yato also has a regalia named Yukine who he has to deal with as Yukine has his own growth and problems.