Turn your oven's broiler on to high and position an oven rack about 6 inches from the heat source.

Heat the olive oil in a large, oven-safe skillet over medium-high heat. Add the sliced bell peppers and onion. Cook, stirring occasionally, for 5-7 minutes, until they are tender-crisp. Add the minced garlic and cook for another minute until fragrant.

Stir in the chili powder, cumin, paprika, oregano, salt, and pepper. Cook for 30 seconds to toast the spices. Add the shredded chicken and the drained diced tomatoes with green chilies. Stir everything together until the chicken is heated through and well-coated in the spices.

Remove the skillet from the heat. Sprinkle the shredded Mexican cheese blend evenly over the top of the chicken and vegetable mixture.

Carefully place the skillet under the preheated broiler. Broil for 2-3 minutes, watching closely, until the cheese is completely melted, bubbly, and starting to turn golden brown in spots.

Remove the skillet from the oven. Let it cool for a minute before serving hot with your favorite toppings.