Prepare the chicken:
In a bowl, combine the shredded chicken with garlic powder, onion powder, cumin, chili powder, salt, and pepper. Mix well to evenly coat the chicken with the seasonings.
Heat the skillet:
Heat a large skillet or frying pan over medium heat. Add the olive oil or butter and allow it to melt and coat the bottom of the pan.
Assemble the quesadilla:
Place one tortilla in the hot skillet. Sprinkle half of the shredded cheddar and mozzarella cheeses evenly over the tortilla. Then, add half of the seasoned chicken on top of the cheese. Place a second tortilla on top to form a sandwich.
Cook the quesadilla:
Cook for 2–3 minutes, or until the bottom tortilla is golden brown and crispy. Carefully flip the quesadilla over and cook for another 2–3 minutes, until the other side is golden and the cheese has melted.
Slice and serve:
Remove the quesadilla from the skillet and let it rest for a minute before slicing into wedges. Serve with sour cream, guacamole, or salsa on the side.
Repeat:
Repeat the process for the second quesadilla.