Black Eagles president Fikret Orman has been locked in talks with City over the Nasri since Tuesday.
Negotiations hit a snag over the payment of his wages but an agreement has now been reached over how City and Besiktas will cover his salary.
Besiktas will pay 60 percent of Nasri’s wages with City paying the bill for the remainder.
Nasri has yet to put pen to paper on the loan deal but his agent is reported to be pleased with the offer on the table and the French international is expected to join the Black Eagles over the next few days.
Besiktas will have completed their second loan deal over the past week if the deal does go ahead as planned.
The Black Eagles brought in 22-year-old Benfica midfielder Anderson Talisca on a one-year loan with an option to extend by one season.