Nemati beat Vincenza Petrilli from Italy 6-5 in the shoot-out and won the gold.
Nemati had previously seized two gold medals in London 2012 and Rio 2016.
The bronze medal went to Chinese archer Chunyan Wu who defeated Dorothea Poimenidou from Greece 6-2.
It was Iran’s ninth gold medal in the 2020 Paralympic Games.
Rouhollah Rostami (powerlifting), Vahid Nouri and Mohammad Reza Kheirollahzadeh (judo), Amir Khosravani (long jump), Mahdi Olad (shot putter), Sareh Javanmardi (air pistol SH1), Hashemiyeh Motaghian Moavi (seated javelin) and Saeid Afrooz (javelin) have already won eight gold medals for Iran.