Heat the olive oil in a large skillet over medium heat.
Add the diced onion and minced garlic. Cook for 2–3 minutes, stirring occasionally, until the onion begins to soften and the garlic becomes fragrant.
In a small bowl, combine the chili powder, sea salt, cumin, garlic powder, and black pepper. Sprinkle the seasoning mixture into the skillet and stir to coat the onion and garlic.
Add the black beans, roasted corn, shredded chicken, diced green chiles, chicken broth, salsa verde, and rice.
Stir everything together until well combined. Bring the mixture to a gentle boil and cook for 2–3 minutes.
Reduce the heat to low, cover the skillet with a lid, and simmer for about 15 minutes.
Remove the lid and check the rice. If it is not completely tender and there is still liquid remaining, cover and continue cooking for a few more minutes.
Once the rice is fully cooked and has absorbed the liquid, turn off the heat.
Sprinkle the shredded Monterey Jack cheese evenly over the top. Cover the skillet again and let it sit for 2–3 minutes, or until the cheese has melted.
Finish with chopped cilantro and, if desired, sliced avocado and a sprinkle of red pepper flakes. Serve warm.