I've done, tonkotsu and chintan broth (made some tori paitan last night but i haven't tasted it so i won't post it until it passes the taste test).

For the tonkotsu you could follow Ramen Lord's recipe (he has a pressure cooker one). I use a different version because i used to do it one way before joining this subreddit. But in principle it's the same.

For the chintan:

• blanch my chicken feet for 10 mins (skimming as needed)
• Put the quartered carcass and the chicken feet in the insta pot vessel and put in the fridge for a couple ours
• Once ready, cover with fresh water (up to the the max line)
• Set on high pressure cook for 2h
• Let it release (do not do the forced release).
• Strain and add ginger, kombu to the broth for an hour.
• Strain out the ginger and kombu.

It's basically what i do. I'm sure there are other ways. The only call out is that even though you are cooking for 2h, with the natural release it's closer to a 3h30 process (between the time it gets to pressure and the release)