Preheat the oven to 425°F. Spray a large baking sheet with cooking spray and set aside.

In a small bowl, combine the chili powder, ancho chili powder, salt, onion powder, garlic powder, ground cumin, paprika, and black pepper.

Sprinkle the seasoning blend all over the chicken breast.

Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the seasoned chicken breast to the skillet and cook for 5 to 6 minutes per side until the chicken is fully cooked through and the internal temperature reads 165 degrees F on a thermometer. Transfer the chicken to a cutting board to rest.

While the chicken is resting, add the remaining 1 tablespoon of olive oil to the same skillet. Stir in the onion and bell pepper, and cook for 3 to 4 minutes until the vegetables begin to soften. Remove the skillet from the heat.

Chop the cooked chicken breast into small bite-sized pieces, then stir them into the skillet with the peppers and onions.

Assemble the quesadilla by placing 6 of the flour tortillas around the edges of the sheet pan, with the tortillas hanging halfway over the edge of the pan, leaving a gap in the center. Place 1 flour tortilla in the center gap.

Evenly spread 1 cup of the shredded cheese over the tortillas, followed by a layer of the chicken and veggies, and another layer of the remaining 2 cups of shredded cheese.

Place the last tortilla in the center of the mixture. Carefully begin folding the tortillas that are hanging over the edge of the pan, towards the middle. Generously brush the melted butter all over the top of the tortillas.

Place a second sheet pan on top of the folded tortillas and press down a bit to hold the tortillas in place. Transfer the stacked baking sheets to the oven and bake for 20 minutes.

Remove the top sheet pan and bake for an additional 5 to 10 minutes until the top is golden brown.

Remove it from the oven and allow the quesadilla to cool slightly before cutting it into 12 servings. Serve with sour cream, salsa, pico de gallo, or guacamole if desired.