Drain chiles, reserving liquid. Coarsely chop chiles; place in a 6-qt. electric pressure cooker. Add tomatoes, onion and reserved drained liquid. Cut roast in half. Combine garlic, salt, cumin and cayenne; rub over roast. Place in pressure cooker. Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 80 minutes. Let pressure release naturally for 10 minutes; quick-release any remaining pressure. A thermometer inserted in beef should read at least 165°.
Remove roast; shred with 2 forks. Return to pressure cooker; heat through. Using a slotted spoon, serve in tortillas with toppings if desired.
Notes
Can you freeze Pressure-Cooker Beef Burritos with Green Chiles?
Freeze cooled meat mixture and juices in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally; add water if necessary.