The Portuguese midfielder has reportedly been deemed surplus to requirements at Old Trafford.
The Portugal international winger is expected to travel to Istanbul this weekend to discuss the move, which will be pushed through for around £3.5 million, according to the report.
The player spent last season out on loan at former club Sporting Lisbon, making 35 appearances and scoring 10 times in an impressive campaign.
It has, however, been made clear by United manager Louis van Gaal that he is surplus to requirements at Old Trafford, reports the Daily Mail, with the likes of Ashley Young and Angel Di Maria already at the club and Memphis Depay having been secured this summer.
A disappointing end to his United career
An eventual exit from Old Trafford will be a disappointing end to Nani’s career in England, with many having hoped he would be a Cristiano Ronaldo mark two when he arrived.
Sadly, despite flashes of occasional brilliance, he was never able to produce consistently in the Premier League under Sir Alex Ferguson, and new boss Van Gaal has clearly decided to cut his losses.
Having said that, at the price being quoted he could certainly still do a job for most Premier League clubs, although his likely high wages would always prove a stumbling block.