The most famous Octagon announcer in MMA history is sick and tired of Nate Diaz's antics, telling the Stockton superstar to stop complaining and start fighting already.
We got Bruce Buffer out in L.A. and he didn't mince words ... saying Nate's public feud with Dana White and the UFC is ridiculous ... considering how much money he's made.
Diaz -- who's scheduled to fight Dustin Poirier at UFC 230 in November -- recently told TMZ Sports he ain't interested in fighting ... and said he felt he'd been "under promoted" by the UFC.
So, when we saw the Buffer out in L.A. earlier this week ... we asked him about Diaz's beef with the UFC.
"Nate, I heard you made 7 or more million dollars on your last fight. I don't want to hear complaining about being under promoted by the UFC."
"You should be thanking the UFC and bowing to Dana White every time you see him."
After Buffer went all Westside Connection on Nate ... we ask him about the trilogy fight between Conor McGregor and Diaz -- and whether that fight's ever gonna go down.