The Absa Premiership rivals will ignite hostilities at 17h00 at Mbombela Stadium in Nelspruit.
"I am happy to join Sundowns and play in South African football," says Nascimento, who joined Sundowns in June following a spell with Academica in Portugal.
"It's a good opportunity to be in the final, this chance to win. I am ready to fight and help my team win the final."
Nascimento backs the league and Telkom Knockout champions to further their collection of silverware, having also booked a spot in the CAF Champions League final last month.
"Sundowns have shown that we can improve in each and every game. There is so much talent. If we can keep focus, we can win many trophies," adds the Brazilian.