The experienced striker, who made his mark at Real Sociedad, has decided to hang up his boots after more than six months without a club
The 32-year-old had been without a club since Besiktas terminated his contract in May after a sub-par campaign in which he failed to score in 17 appearances.
"I would like to share my decision to put an end to my professional career as a footballer," a statement from Nihat read.
Nihat broke into Besiktas' first team in 1997 and featured for the Istanbul-based club until 2002, when he moved to Real Sociedad.
At the Primera Division club, the striker formed a great partnership with Darko Kovacevic and finished joint second with Real Madrid's Ronaldo in the scoring charts in 2002-03.
Nihat also played at Villarreal between 2006 and 2009 before returning to Besiktas, where he failed to make his mark and even clashed with team-mate Ricardo Quaresma and a journalist.
He won 69 caps for Turkey, helping his country to a third-placed finish at the 2002 World Cup finals in South Korea and Japan.