Prepare ingredients by cutting the chicken into 1–2 inch pieces and rinsing the rice.
In the Instant Pot, add the cubed chicken, drained black beans, frozen corn, salsa, chicken broth, and taco seasoning; stir to combine.
Add the rinsed rice on top of the mixture but do not stir it into the liquid.
Secure the Instant Pot lid, set the valve to sealing, and cook on high pressure for 10 minutes.
When the cooking time is done, perform a quick release carefully and remove the lid according to the manufacturer's instructions.
Stir the mixture to combine; the chicken should be tender and pull apart easily.
Sprinkle the shredded Mexican blend cheese over the top, cover with the Instant Pot lid (or a plate) and let sit a few minutes until the cheese melts.
Scoop into bowls and top with diced avocado, sour cream, and cilantro as desired.