According to Metro, the 'Foundations' singer made the comments at London's O2 Arena as part of a music masterclass for Brit School hopefuls.
Talking about the reality talent show, Nash said: "It depends whether you want to be an artist or a celebrity. I don't really have respect for The X Factor."
She also added that the programme is "depressing" and "really disturbing".
Nash, a former Brit School student, has criticised The X Factor in the past, comparing it to "junk food" and suggesting that no-one on the show "is an actual artist".