The card, dubbed UFC Fight Night Tokyo, will take place at the Saitama Super Arena and stream on UFC Fight Pass, officials wrote in a statement.
Hunt (9-8-1) last fought in one of the most memorable bouts in UFC history, when he and Antonio “Bigfoot” Silva exchanged blows for five rounds last December. The match ended in a draw, and Silva later tested positive for elevated testosterone.
Nelson (20-9) will come into the September fight off a win over Antonio Rodrigo Nogueira at UFC Fight Night Abu Dhabi. The finish of Nogueira was Nelson's 18th career win within the distance.
The Hunt-Nelson main event will be a five-round fight.
(Image via UFC Instagram)