Minaj, who is also a co-judge alongside Randy Jackson and Keith Urban on the hit-talent competition, wore her signature blond wig, a pink dress and blazer, and gold necklace.
American Idol's 12th season premiere will air on Fox this Wednesday.
When asked about attending the LaGuardia performing arts high school, Minaj said she developed a passion for acting there, and also noted the school's lack of diversity.
"I felt that I was at home because all of the other kids were crazy like me, but I was the only black girl in the school.
"There was like two black people in the entire drama class, and I was the other one. And I'm still friends with the other black girl.”
On whether she has a temper, Minaj told Leno: “I wouldn’t say I have a temper … Last year, I did. In 2013 baby, I am on the road to recovery. Yes ma’am!”
At the "American Idol" auditions in October in Charlotte, N.C., Minaj had a heated altercation with her co-judge, Mariah Carey, as Keith Urban sat between the superstars.
“I told them I’m not [expletive] putting up with your [expletive] highness over here,” Minaj reportedly said during the interaction.
Meanwhile, Carey’s responses are inaudible in a video that was released by TMZ.
Taping for the hit talent competition was halted after the shouting match.
Minaj told Leno that she loves Carey. “I’m one of her biggest fans in the world, darling. [...] It definitely wasn’t a fake feud, that I can say for a fact. It’s just one of those weird things you’d have to see to get it.
"A lot of it starts off with us just joking but we are passionate, and both crazy and then sometimes it just goes *makes cat noise*.”
Watch Nicki Minaj’s interview with Jay Leno here.