Iran’s reigning Paralympic silver medallist Nikparast claimed the silver with a throw of 62.74.
In his Paralympic debut, Uzbekistani teenager Aleksandr Svechnikov set the bar early in his second attempt (65.69), en route to the gold.
Serbia’s World bronze medallist Nemanja Dimitrijevic (60.86) chased the 18-year-old but managed silver and bronze.
Iran has participated at the 2016 Summer Paralympics with 111 athletes in 12 sports.
The Iranian delegation finished in 11th place in the previous edition, winning 10 gold medals, seven silvers and seven bronze medals.