Stem and seed the peppers and cut into chunks. Coarsely chop the onion and garlic. You don't have to be too fussy since later the sauce will get blended.
Put everything not labeled "for serving" in the pressure cooker without adding any water. The produce will release enough water to create steam. Pressure cook for 15 minutes.
Release pressure. Remove the chicken with tongs and allow it to cool.
Blend the sauce with a blender or food processor.
Remove the bones and skin from the chicken and rip it into smaller chunks. Return to the sauce. Adjust seasoning.
Serve with cilantro, lime wedges, and corn tortillas.
Plan ahead to spare your fingertips! The chicken takes quite a while to cool down enough to comfortably handle if you have wussy hands like me.