The fight is one of seven set for the Dec. 9 card. A co-main event will be announced soon.
The 33-year-old Swanson (25-7) is on a four-fight winning streak, the latest coming in April when he defeated Artem Lobov by unanimous decision. He fights out of Palm Springs and is ranked No. 4 in the division.
Fighting out of Torrance, Ortega (12-0) fought in July and won by submission over Renato Carneiro. Ortega, 26, will come into the main event ranked No. 6 in the featherweight division.
Ortega’s first UFC fight occurred in 2014, while Swanson made his debut in 2011.
Tickets go on sale Oct. 20.
UFC Fight Night in Fresno
A look at the early card for the UFC Fight Night at Save Mart Center on Dec. 9.
- Featherweight main event: Cub Swanson (25-7) vs. Brian Ortega (12-0)
- Flyweight: Alex Perez (18-4, 3 KO/TKO, 5 submissions) vs. Carls John De Tomas (6-1)
- Middleweight: Antonio Braga Neto (9-2-0, 1 no contest) vs. Trevin Giles (10-0-0)
- Women’s flyweight: Alexis Davis (18-7-0) vs. Liz Carmouche (10-5-0)
- Middleweight: Eryk Anders (9-0-0) vs. John Phillips (21-6-0, 1 no contest)
- Lightweight: Scott Holtzman (10-2-0) vs. Darrell Horcher (13-2-0)
- Featherweight: Chris Gruetzemacher (13-2) vs. Davi Ramos (6-2)