Toure has scored 19 goals for City this season, and the Frenchman has talked up the talents of the powerful Ivorian.
Speaking to Sky Sports News, Nasri said: "He's a world-class player. You can describe him with every word. He's powerful, he has technique, he has everything.
"For me, like I say, he's one of the top three midfielders in the world."
City travel to Everton this evening.