Peyton Manning -- Legal Weed In CO ... Has Been GREAT for Pizza Biz

Legalized pot has been very, very good for Peyton Manning ... especially in Colorado ... because the QB says new weed-friendly laws in the Mile High State have been great for his pizza business.

The Denver Broncos superstar -- who owns 21 Papa Johns franchises in the Denver area -- was talking with Sports Illustrated's Peter King when he was asked about voting and laws in CO.

And that's when Peyton dropped this gem -- "There’s some different laws out here in Colorado. Pizza business is pretty good out here, believe it or not, due to some recent law changes."

Doesn't take a rocket-scientist to figure out he's talking about Colorado's new laws legalizing recreational marijuana ... and clearly, Peyton's learned stoners love pizza.