I’d let them take a break from each other. I’ve heard recommendations from anywhere between a few weeks to a few months depending on how bad the fight, to let grudges fade and for them to forget the fights.

During that time, it couldn’t hurt to give them both stuffie friends. After a few days, make sure the stuffie is covered with their scent, swap plushie friends. If they’re still aggressive towards each other, it’s a nice way to get them used to each other’s scent again and to get them used to sharing and living with each other’s scent. Continue swapping plushie friends until you try bonding again.

If it was just a scuffle you can let them cool off before trying to go back a step to when it was still working, ie back to neutral dates. Make sure the interaction ends positive for them as well.

Instead of allowing them into each others homes, by just opening the gate, give them a common area to chill in together. (For me a common area was my sitting room-both my buns spent time there, but they knew it wasn’t their home, so they didnt feel compelled to defend it-but it was still not neutral and did smell like the themselves. I also only gave them a very small area of it in which to hang out, which I increased as time wore on.)
Your buns should be showing total comfort with each other in the stage before you move on to the next. So you’d want to see Moxie and Nibbles happily grooming, or just relaxing together with no fighting in a neutral zone before moving to a common area and the same thing in the common area before letting them into a ‘home’ environment for one or the other.

If it was a big fight, you’ll need to give them a good amount of cooling off time like Sleepy has said, and then let them start from the very beginning again.