Season the chicken with salt and pepper. Place in an Instant Pot with the enchilada sauce and pressure cook on high for 12 minutes. Let the steam release naturally, about 10 minutes. Shred the chicken with two forks, remove from the liquid with a slotted spoon and let cool.
Assemble the bowls starting with lettuce then add the chicken, beans, corn, peppers, tomatoes, cheese, and avocado in groupings. Serve with dressing.