Amanda Nunes, Felicia Spencer make weight for UFC 250 featherweight title fight

Cormier explains why Spencer presents stylistic challenges for Nunes (0:46)

Daniel Cormier previews the main event at UFC 250 between Amanda Nunes and Felicia Spencer for the women's featherweight title. (0:46)

The top women's fighter in the world made her return official.

Amanda Nunes weighed in at 145 pounds Friday morning at the UFC 250 official weigh-ins in Las Vegas. Nunes will defend her UFC women's featherweight title against Felicia Spencer in the main event of the card Saturday night at the UFC Apex. Spencer weighed in at 144.5 pounds.

ESPN has Nunes ranked as the No. 1 pound-for-pound women's MMA fighter in the world. Nunes is the UFC women's featherweight and women's bantamweight champion. Spencer is UFC's top contender at women's featherweight. This will be Nunes' first defense at 145 pounds.

Nunes (19-4) has won 10 straight fights with five bantamweight title defenses. She has the most wins in UFC history among women (12) and the most wins in UFC title fights among women (7). Nunes, 32, has beaten every fighter who has ever held the UFC women's bantamweight and featherweight titles, including Ronda Rousey, Holly Holm and Cris Cyborg.

Spencer (8-1) is coming off a first-round TKO win over Zarah Fairn Dos Santos in February. The Florida resident is trying to become only the third Canadian to win a UFC title. Spencer, 29, has only one career loss -- to Cyborg at UFC 240 in July.

The co-main event is also set, as both former bantamweight champion Cody Garbrandt and Raphael Assuncao weighed in at 136 pounds.