The guy that does them for NA uses Hypercatcher (iOS only?) but you should be able to update the feed at anytime but that’s a question for nostr:npub19ha7tju4teqp3dmwv4p28wrcy9zd6h6hxkg5mwvjrlfycweazpkse2q0fa and nostr:npub18gp8p84hjmjh9zejdlyqqcg22sj6x3qra0q2ng4v6cxxg95sav8q0mcg5e as I’m just a simple listener.
Discussion
Chapters are a simple json file (easily handhacked) which you add under the episode
https://podcasting2.org/podcast-namespace/tags/chapters
And if you want to see an example, here is my Homegrown Hits RSS feed:
Sweet thanks. I'll give it a shot. I'm using castapod to host my rss feed and I can't remember if they have a gui for this. But they for sure allow you to modify the json so I should be good to try it.
This is my favorite chapter builder: https://github.com/CplPibald/pc20chapters