Navas moved to City last week from Sevilla.
Iniesta said: "Navas is a very special player. He is going to cause the defences in the Premier League a real problem when he plays for City.
"Jesus has so much speed, and his feet are so quick, that it becomes nearly impossible to stop him without fouling him.
"The only player that I can compare him with that is already playing in England is Gareth Bale."