Preheat your oven to 375°F (190°C).
Dice the green and red bell peppers and onion into bite-sized pieces.
In a mixing bowl, combine the cumin, garlic powder, smoked paprika, salt, oregano, and cayenne pepper (or red pepper flakes). Add the chicken breasts and drizzle with 1 tablespoon of olive oil. Rub the spice mixture all over the chicken.
Place the seasoned chicken breasts in your baking dish. Scatter the chopped bell peppers and onion around the chicken. Drizzle with an additional tablespoon of olive oil.
Cover with aluminum foil and bake for 25 minutes.
Remove the foil, place the slices of pepper jack cheese on top, and bake uncovered for an additional 10-15 minutes until the chicken is cooked through and the cheese is bubbly.
Remove from the oven and let it rest for a few minutes before serving.
