Prepare the marinade: Place all the ingredients except the chicken in a food processor. Pulse until the mixture is mostly smooth. Place the chicken thighs in a large bowl and pour in the marinade. Toss chicken in the marinade until well-coated. Cover the bowl and place in the refrigerator to marinate at least 1 hour or up to 8 hours.
Cook the chicken: Place the chicken and marinade in the Instant Pot. Press the Manual Button and set the timer for 30 minutes on high pressure. Naturally release or manually release the pressure once cooking is complete. Remove the chicken to shred and then return to the pot to soak in the juices until ready to serve.
* Remove the ribs and seeds of the peppers to reduce the spiciness of the marinade.