Nicki Minaj PISSED at 'American Idol' Producers -- Stop Fueling Mariah Carey!

Nicki Minaj is FURIOUS with "American Idol" producers -- telling her peeps they goosed Mariah Carey into starting beef on the set.

Sources connected with Nicki tell us ... she's convinced producers -- along with members of Mariah's team -- are conspiring to get under her skin ... because they think a pissed off Minaj will bring in viewers.

We're told Nicki is adamant ... she won't be anyone's puppet and if she feels she's being set up, she vows to "cut it off at the head." As for how, she says for starters, the next time Mariah "acts up," Nicki is walking off the set.

There's just one problem with her theory -- we know "Idol" producers were genuinely shocked and upset by Tuesday's outburst. Our very connected "Idol" sources tell us the big wigs were completely flat footed and they are doing everything they can to restore peace -- which they successfully did Wednesday.