Cooking frozen chicken thighs in Instant Pot, oven, air fryer or boiled without thawing is easier than you think. How to get chicken fork tender from frozen.
Lay frozen thighs into the bottom of you pot (separated from one another, not in a huge clump turns out a lot better). Pour your sauce over the top. Close lid and steam valve shut.
Cook on high pressure for 20 minutes, then allow to naturally release the steam for 10 minutes.
Open and remove lid. Use a fork to separate pcs. and shred meat. If they were separated at the beginning they will likely be tender enough to serve over rice.
If they were in a big chunk at the beginning they won't be quite tender enough yet. In this case after shredding as much as you can, or chopping into smaller pcs. on a cutting board and putting back into the pot, set to saute.
Allow the contents to bubble and let the meat get more tender for about 3-4 minutes. Turn off when it is fork tender and serve over rice.