Kayla Harrison Still Hoping For Amanda Nunes Fight Despite Retirement

Kayla Harrison is still itching for a fight with Amanda Nunes ... telling TMZ Sports if the UFC's G.O.A.T. ever comes out of retirement, she wants to throw hands with her badly!!!

But, don't get it twisted ... there's absolutely no bad blood on Harrison's end toward Nunes -- she just wants the scrap to prove that she can beat the best ever.

"She is the greatest of all time," Harrison said of The Lioness. "She was the woman. And I wanted to be the woman. And, to me, that's like the greatest compliment I can give someone. I value what you have so much and who you are so much that I'm like chasing you."

Problem for Harrison is ... it doesn't seem like Nunes has any intention of getting back in the octagon ever again.

You'll recall ... the 35-year-old officially called it a career after she beat Irene Aldana at UFC 289 last month -- and she seemed dead serious about the decision, saying it was "the perfect night to retire."

Harrison tells us it all bummed her out -- even though she was ultimately happy for her former training partner.

"She's done everything she's wanted to do," Harrison said. "She's got a beautiful family, she's living the dream."