Nelson (16-3) wasn't pleased with the circumstances of that loss -- Ponzinibbio landed several early eye-pokes that went uncalled -- and even appealed the official result.
Regardless of his feelings toward the outcome, however, the 29-year-old Nelson recognized the head trauma he'd just suffered. And that's not something Nelson has ever taken lightly.
"I still got knocked out," Nelson told ESPN. "I want to give my brain and body time to recover from that. I've seen a lot of guys going back in there early and, obviously, that's what you want to do. You want to pick it right back up. You didn't feel it was a good one and you want to make up for it.
"On the other hand, I'm looking ahead. I don't want to develop a glass chin because I went back in there too quick."
It seems like an obvious thing: A human being, caring about the health of his or her brain. However, that doesn't always seem to be the case in combat sports. Just last month, veteran Michael Bisping suffered two losses in the span of three weeks -- to Georges St-Pierre and Kelvin Gastelum.
Bisping, 38, went to so far as to secure a shortened medical suspension from the New York State Athletic Commission in order to face Gastelum. Bisping was knocked out cold in the second fight, and admitted this week it was probably "the wrong move."
Following his loss to Ponzinibbio, Nelson received a 30-day "no contact" medical suspension from the UFC. He basically quadrupled that on his own.
"I resumed light sparring about one month ago," Nelson said. "I've actually seen a neurologist a couple times and he was talking about how there can be damage to your brain that doesn't show up on a scan. So they're not major injuries, but they take a long time to heal.
"The danger is, if you get hit or concussed again, and it doesn't even have to be that hard, that can cause long-term damage. I've had a few scans; my brain is perfect, and I want to keep it that way. I don't want to have problems down the line when I'm getting older, spending time with my kids and my kids' kids. I want to be sharp."
After taking the medical precautions he felt necessary, Nelson says he's ready to start discussing his next fight.
Nelson expressed interest last month on social media in a fight against Darren Till, but says he hasn't heard a word from the UFC on the potential matchup. He believes it's likely he'll return at a UFC Fight Night on March 17 in London.
Coming into 2017, Nelson believed he was in position to face a top-10 opponent. He ultimately didn't draw one, settling on fights against Alan Jouban and Ponzinibbio instead.
Despite the fact he's technically coming off a loss, Nelson believes the UFC is aware of the impact Ponzinibbio's eye-pokes might have had in that fight, and he's still expecting a top-10 opponent.
"There was plenty of evidence," Nelson said. "I can't see anyone looking at the film and thinking that wasn't a major factor. I wanted Darren Till, but maybe he or the UFC have different plans.
"I would love to fight Ponzinibbio again, if that were a possibility. Colby Covington is someone I'd fight as well. He's done well for himself. I'd definitely be excited to fight him."