The changes have been made in a bid to revive the struggling Thika United to the winning side.
Nandwa, who has been plucked from Jericho All Stars where he has been coach, stated that he was upbeat and looking to get the team back to winning ways.
Nandwa begun training the team today and is hopeful in getting positive results.
“The season has only gone five weeks so we have ample time to turn it round,” Nandwa said.
Nandwa formerly coached Utalii, Karuturi, AFC Leopards, Shabana and also Tanzanian side Coastal Union as well as the national team.
Irungu was elevated to the head coach’s position following the resignation of Briton Tim Bryett last year but the youthful tactician has struggled in 2016 with the team yet to win a league game.