Select the saute function on the Instant Pot. Once hot, coat with oil. Place the 4 pieces of pork in the IP, and saute on all sides until lightly browned (less than 8 minutes total). Remove the pork, set aside. Select cancel.
De-glaze the pan with the juice from the oranges and limes. In a small bowl, combine the spices. Combine with the orange/lime juice inside the IP. Place the pork inside, then top with onion and garlic. Secure the lid. Set your oven to broil (optional)
Cook on high pressure (manual) for 25 minutes. Use a quick release. Remove the pork and shred with a fork. Place on a baking sheet and add to oven. Broil for 4-5 minutes (optional, but such a great step to finish off).
Serve hot and spoon additional sauce from the IP on top of the pork. You can wrap in tortillas, serve in a bowl of greens, serve over rice, or serve over cauliflower rice. Garnish with cilantro and any other additional toppings you enjoy.