The Frenchman has endured a mixed spell at the Etihad since leaving Arsenal in 2011 following reported spats with former boss Roberto Mancini, but has enjoyed a positive start to the current campaign.
City face the Champions League holders on Wednesday, and Ribery is fully aware of the threat possessed by Nasri.
"Samir is a new person", Ribery told a press conference. "He is like a brother to me.
"Here we see the Samir of his time at Arsenal. He is one of the most talented players in Europe."
City host Bayern in the Champions League at the Etihad on Wednesday.