He was the protagonist against McGregor and then the 4 fights after that.
In pretty much every fight the majority of fans want Nate to win.
Against Conor his fan-backing reached a new level.
McGregor is the biggest PPV star in MMA because people tune in as both fans and haters.
With Nate, people are almost exclusively tuning in because they like him.
With his last fight, against another fan-favorite guy, Tony Ferguson, it became a showcase of Nate vs. the UFC.
Even though he has a lot of losses, he's a genuine guy who refuses to let anything break his mental frame.
He got to leave the UFC on his own terms. On a win. As a superstar who again flipped the MMA world on its head with all the shenanigans. He got to make Khamzat "lose" to him without even fighting him. In one night, he beat Tony, Khamzat, and the UFC.
If he fights Jake Paul and beats him, MMA should just be called Nate Diaz like Naruto is named after the protagonist of the series.