The 54-year-old coach replaced Majid Jalali in Ghaemshahr-based football club.
Nassaji finished in 10th place in Iran Professional League (IPL) last season.
Mohajeri led Machine Sazi last season and now is going to start a new challenge in another Iranian top-flight football club.
Mohajeri started his coaching career in Shirin Faraz in 2011 and has also coached Siah Jamegan and Padideh.