In a small bowl, mix together the chili powder, cumin, garlic powder, onion powder, paprika, salt, and pepper. Toss your chicken pieces in the spice blend until they are evenly coated. Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook for 5-7 minutes, stirring occasionally, until it's cooked through and lightly browned. Remove the chicken from the skillet and set it aside.

In the same skillet, add a little more oil if needed. Add the diced onion and bell pepper. Cook for 3-4 minutes, until they are soft and slightly caramelized.

Lay a tortilla flat. Sprinkle a generous layer of the cheese blend over one half of the tortilla. Top the cheese with a portion of the cooked chicken and sautéed vegetables. Sprinkle another layer of cheese on top of the filling. Fold the other half of the tortilla over the filling.

Wipe the skillet clean and reduce the heat to medium. Melt a small amount of butter or add a touch of oil. Carefully place the assembled quesadilla in the skillet. Cook for 2-3 minutes per side, until the tortilla is golden brown and crispy, and the cheese is completely melted.

Remove the quesadilla from the skillet and let it rest for a minute before cutting it into wedges. This helps the filling set. Serve immediately with your favorite toppings.