Step 1

Turn the Instant Pot to SAUTE and add the oil. Once the oil is hot and shimmering, add the chicken, onion, and salt. Cook and stir, breaking up the chicken as you go, until the meat is no longer pink, about 7 minutes.
 Add the red bell pepper, green bell pepper and black beans, corn, chili powder, cumin, and garlic powder. Stir to combine.

Step 2

Splash in the water and scrape up all of the stuck on bits of food. Make sure to get every bit off so that you avoid a burn warning. Pour in the diced tomatoes in their juices and salsa. Do not stir. Rinse the brown rice and drain (this will help prevent a "burn" warning). Add the brown rice and once again do not stir (again, we are trying to avoid the burn warning here). With the back of a spoon or a spatula, gently push the rice down and spread it evenly so that it is submerged in liquid.

Step 3

Cover and seal the Instant Pot. Cook on high pressure (manual) for 20 minutes. Allow the pressure to release naturally for 20 minutes, and then vent to release any remaining pressure.
 Remove the lid and stir. At this point, the rice may still have a bit of liquid at the bottom, but it will continue to absorb as the casserole sits. Taste and adjust any seasonings as desired.

Step 4

Stir in 1/2 cup of the shredded cheese, then sprinkle the remaining cheese over the top. Set the lid back on the Instant Pot (no need to seal; just make sure it is resting on top). Let rest 10 additional minutes to allow the cheese to melt and more of the liquid to absorb. Serve hot with any desired toppings.