Place all ingredients into your instant pot bowl in the following order: 2 chicken breasts, drained black and white beans, chopped onion, corn with juice, tomatoes with juice, and 1/2 cup chicken broth.
Add 1/2 to 1 tsp chili powder, 1 teaspoon cumin, and the ranch packet. Stir everything to combine, getting some of the juice under the chicken to keep it from scorching.
Cut cream cheese into 6 pieces and place over the top of chili. Cover and seal with lid. Switch the valve to the sealing position and cook for 20 minutes on manual high pressure. Once it is done cooking, let it naturally depressurize for 10 minutes and then switch the valve to the venting position to completely release steam before opening lid.
Remove the chicken breasts to a plate and shred apart with 2 forks. Stir everything together in the pot to melt the cream cheese into the chili and then return the shredded chicken and stir to combine. Serve garnished with avocado and cilantro if desired.