Add all ingredients to the inner pot of your Instant Pot.
Place the lid on the Instant Pot, then pressure cook on High Pressure for 1 hour. When it's done cooking, use a full natural pressure release. Open the lid after no more pressure remains and the pin drops.
Transfer the Barbacoa to a serving platter. It should be tender enough to pull apart with tongs or shred with a fork. For a milder Barbacoa, remove the chilis before shredding. For a spicier Barbacoa, shred the roast together with the chipotle pepper.
Serve your Instant Pot Barbacoa in tortillas with your favorite taco toppings.
Notes
Nutrition information does not include calculations for toppings or sides.