UFC president Dana White broke the news via social media on Tuesday. The new 135-pound matchup will headline the pay-per-view event, which takes place at Rogers Arena in Vancouver.
"Unfortunately, [Peña] broke her ribs and she can not compete," White said on Instagram. "We have Irene Aldana coming in, who has won four of her last five and three of those were finishes. We could have another Mexican world champion."
Aldana (14-6) is a former Invicta FC title challenger with an 8-4 record in the UFC. She has won six of her past eight, including a first-round knockout of Ketlen Vieira in 2019.
Her most recent loss came at the hands of former champion Holly Holm in October 2020. She is vying to become the fourth active Mexican-born champion, alongside flyweight Brandon Moreno, interim featherweight champ Yair Rodriguez and flyweight Alexa Grasso, her teammate at Lobo Gym.
Nunes (22-5) is universally considered the No. 1 pound-for-pound female fighter in the world. She suffered a shocking upset against Peña in December 2021 but bounced back in dominant fashion with a decision win over her last July.