The former UFC bantamweight champion was dethroned after being submitted in the second round via a rear-naked choke in the co-main event of UFC 269 last December.
However, Nunes has refused to accept responsibility for the loss, as she insists she wasn’t fully ‘100 percent’ going into the fight.
She told ESPN. “My whole camp for this fight was a mess.
“I always want to put in my head I was okay, I can do this because we are like that.
“We want to go through whatever to step in the cage, and my first fight against her fell through.
“I got COVID, so all those things and in my second fight with her, the camp I went through a couple of issues, as well, that I knew I wasn’t going to be able to really show up to the gym every day at 100 percent.
“But I didn’t want to let that fight go again. I don’t think it would have looked good for me.
“I paid for it. I paid for my mistakes.
“I was supposed to listen to the doctors, I was supposed to listen to my body and show up how I always do, 100 percent in the gym, full camp, and it was obvious in the fight.
“I really showed how my camp was, and I feel like I paid for it.”
Nunes and Peña, 33 and 32 respectively, have been named as coaches for the upcoming 30th season of The Ultimate Fighter reality series.
The pair are expected to rematch after the filming of the show later this year.
And the former champ feels she ended up paying for her mistakes as she didn’t take the time to heal properly.
Nunes continued: “Both knees were pretty bad, and I wasn’t able to recover, and I went through.
“Every time I was training back home and the next day I couldn’t even walk but I don’t want to make excuses.
“I did that. I paid for my mistakes, but I want to do a full camp, and I didn’t. I needed time off.
“I couldn’t turn, do all the things that I have to do, like do jiu-jitsu that much, wrestling.
“I was pretty much only doing hands like striking or whatever I did for conditioning. I only used my arms, so that cost me my belt.
“In the beginning of the second round, I got caught. I watched the fight back, and I told Nina I never got caught before, so I never felt [it].
“I didn’t know how it is, so when I watched the fight back, I saw that she did a Superman punch, which looked like a jumping overhand, something like that, so it got right here on my head.
“After that moment, you can see clearly that I lost my balance and everything started to look really bad.
“So a lot of people say my conditioning. No, when you get caught, you feel [something] you’ve never experienced in the gym or whatever.
“Getting caught you don’t know how you’re supposed to feel or handle that moment, so when I felt it, I wasn’t able to recover and everything started getting worse.”