Add the olive oil to Instant Pot. Press Sauté function on high setting. Once hot, add pork chunks and brown on all sides for about 10 minutes. Cook in batches if needed. Add all of the rest of the ingredients and mix well to combine.
Put lid on and secure closed. Press Cancel and then press Pressure Cook on High for 30 minutes. Let Instant Pot Manual Release on its own for 20 minutes, then remove lid.
While Instant Pot is slow releasing, turn oven on to broiler.
Use slotted spoon to remove pork and onions from Instant Pot and place on a lined baking sheet. Gently pull pork apart with two forks. Squeeze fresh lime juice on pork and then broil for 2-3 minutes, or until pork is brown and crispy. Watch carefully so it does not burn!
Garnish with lime wedges and cilantro. Serve with tortillas and your favorite taco fixings!