Nuno has resigned as Valencia manager, the Portuguese coach announced on Sunday.
Nuno, who took charge at the Mestalla in June of 2014, guided Valencia to a Champions League place last season. But he has seen his side slump to a disappointing ninth place this campaign.
"The situation is not good and I'm an employee of the club," the former Rio Ave said following his side's 1-0 loss at Sevilla on Sunday.
"It has been an honour to coach Valencia. I want to thank all the players for their efforts and thank [owner] Peter Lim and the fans of a great club.
"We have the youngest squad in the league and it is important Valencia follow through and believe in this project.
"On Monday there will be a meeting to clarify the future."
Nuno, 41, indicated that he'd made his decision to step down before Sunday's match.
Press Association contributed to this report.