The daily Turkish newspaper HaberTurk state that Valencia are poised to unveil the transfer today and are expected to make an announcement.
Fenerbahce will make a £2.5 million profit just a season after signing Nani for £4.5 million from Manchester United on a three-year deal.
Meanwhile DHA reported that United were also interested and had agreed personal terms but the deal stalled due to his release clause being more than what he was sold for just last season.
Nani scored 12 times and provided 13 assists for Fenerbahce last season but fell out of favour with head coach Vitor Pereiera.
The 29-year-old winger has been one of Portugal’s star performers at the European Championships and will is the joint top scorer with two goals – alongside Cristiano Ronaldo.