The rapper lost her rag as the judges criticised a 20-year-old hopeful during the show's visit to Charlotteville, North Carolina.
Keith Urban asked Summer Cunningham how she saw herself as a singer, and she nervously replied: "‘I did the country thing so maybe a soulful county thing is what I have been doing."
But country star Keith didn't like her answer and grumbled: "I always get thrown when people say they have 'done the county thing', it's like saying you 'did the brain surgeon thing'. Either you are a brain surgeon or you're not."
And once Mariah Carey joined in to tell the youngster that she'd upset Keith, Nicki decided enough was enough.
"Why are we picking her apart because of a country comment? You guys make comments about everybody in popular music all day," she ranted. "Not you Keith... Randy and Mariah."
"Oh really, is that what I do?" Mariah responded incredulously. "I'm trying to help her as opposed to just talking about her outfit."
And veteran music industry figure Randy Jackson chipped in: "I'm just trying to help you, a little bit, 30 years. Insight."
But Nicki seemed to take this the wrong way, declaring: "Oh, you’re right. I'm sorry I can't help her. Maybe I should just get off the f****ing panel."
And with that she rose and left.
Mariah joked: "That was my move. I was gonna do that the next time she bagged on me."
But a seething Minaj told her to "shut the f*** up"’ from the sidelines, before saying generally: "Finish the show. I'm done."