Heat a large skillet or pot over medium heat and add the olive oil.
Add the cubed chicken and diced onion and sauté 2–3 minutes, stirring, until the chicken is cooked through and onions are lightly browned.
Stir in the black beans, corn, diced tomatoes, diced green chiles, chunky salsa, rice, taco seasoning, cumin, chili powder, salt, and pepper until evenly combined.
Pour in the chicken stock or water and bring the mixture to a gentle boil.
Cover, reduce heat to low, and simmer 15–20 minutes, or until the rice is tender and liquid is absorbed.
Remove from heat and sprinkle with shredded cheese; let sit 2 minutes to melt.
Serve bowls topped with sliced avocado, diced tomato, sour cream, and cilantro as desired.
