Nelly is so pissed judges awarded Devin Haney the win over Vasiliy Lomachenko, he says he's done watching the sport -- he's finished with boxing!
And, the 3x Grammy award winner isn't alone ... lots of fans are pissed off at yet another controversial decision.
"I'm just letting y'all know I am done with boxing," the 48-year-old rapper said. "They will never get another motherf***ing dime out of me."
"This is a travesty! I am done with boxing!"
The highly contested fight went down Saturday night in Las Vegas .