Season the pork chops with salt and pepper.
Turn the Instant Pot to the Saute function and place ½ a tablespoon of butter in the pot until it melts. Sear the pork chops for 2 minutes on each side.
Remove the pork chops and add the remainder of the butter to the pot.
Saute the onion and mushrooms until the onions are softened. Add the garlic and stir until the garlic is fragrant.
Pour in the broth, soy sauce, and thyme. Scrape any bits off the bottom of the pot. This is called deglazing to prevent the burn notice coming up while pressure cooking.
Add the pork chops back into the broth.
Top the Instant Pot with the lid and seal the vent. Turn the pressure cooker on high. Set the timer for 5 minutes. Once it is done cooking, allow the natural steam to release for 8 minutes.
When the pork chops are done, remove them from the broth. Use a slotted spoon to remove mushrooms and place them in a bowl to use as a side.
Turn the saute function back on. Combine cornstarch and water and whisk to make a slurry. Use a whisk and continue to stir the gravy as it thickens.