In a mixing bowl, combine the shredded chicken with chili powder, cumin, garlic powder, salt, and pepper. Mix thoroughly until the chicken is evenly coated.

Dice the medium bell pepper and red onion into uniform pieces, about ¼-inch in size.

Lay a large flour tortilla flat. On one half, sprinkle half of the Mexican cheese, layer with seasoned chicken, diced bell pepper, onion, and top with Monterey Jack and remaining Mexican cheese before folding.

In a skillet, heat olive oil or butter over medium heat. Place the assembled quesadilla in the skillet and cook for 3-4 minutes until golden brown. Flip and cook the other side for an additional 3-4 minutes.

Remove the quesadilla from the skillet and let it rest for 2-3 minutes. Slice into triangular wedges.