In your instant pot, add cubed pork butt + raw onion. Pour over the chicken stock, orange juice, lime juice, oregano, salt, pepper + bay leaves. Stir to combine. Close with the lid, and make sure the vent is at SEALING.
4 pound boneless pork butt, 1 yellow onion, 2 cups chicken stock, juice from 1 orange, juice from 2 or 3 limes, 1 tablespoon dried oregano, 1 tablespoon kosher salt, 2 bay leaves (optional)
Close with the lid, and make sure the vent is at SEALING. Cook on HIGH PRESSURE for 30 minutes. Will take about 10-15 minutes to reach pressure, then it will start counting down from 30. After the 30 minutes is up, do a QUICK RELEASE, where you move the valve to VENTING to release all the steam. Once all the steam is gone and the float valve has dropped, you can safely open the instant pot.
Set your oven to BROIL.
Gently remove all the carnitas and cooked onions, transferring them to a rimmed baking sheet. Discard the bay leaves. Shred the carnitas using 2 forks. Pour 1 a cup of the cooking liquid from the instant pot over the carnitas.
BROIL the carnitas for 5 minutes, until crispy. If I have time, I like to turn the carnitas 3 or 4 times and keep broiling in 5 minute increments. This really caramelizes the fat and gives it the most amazing texture and flavor.
Serve warm topped with chopped cilantro. Delicious in burrito/taco bowls with fajita veggies, cauliflower rice, guacamole + salsa. Can also serve as tacos or as a salad.
Will keep in an airtight container for 5 days, or frozen for 6 months.
See the Recipe Notes below for more tips, FAQ's and ingredient substitutions.