UFC's Valentina Shevchenko: I'm the REAL Champ ... Bring On Nunes, Rousey!

UFC badass Valentina Shevchenko -- who beat up Holly Holm this weekend -- tells TMZ Sports she wants the belt ... BADLY ... and she's ready to go through Amanda Nunes or Ronda Rousey to get it.

FYI, Shevchenko lost to Nunes by unanimous decision back in March -- but Valentina says she's at the top of her game now ... and is champing at the bit to get the current UFC women's bantamweight champion back in the Octagon.

"I know it will be a very difficult fight for her," Shevchenko said ... "I want it. I want it very much."

She also pitches her case to UFC honcho Dana White about why she should get the rematch.