The 41-year-old coach replaced Masoud Shojaei in the Tehran-based football club, according to Tasnim News Agency.
Under leadership of Shojaei, Havadar finished 13th in the 16-team table.
Rahmati stepped down as the head coach of Nassaji in November 2023 following poor results in the top flight team.
Rahmati played for Iran’s national football team from 2004 to 2014. He also played for Esteghlal in two stints.