Add ingredients. Sprinkle the cheese over one-half of the tortilla. Add chicken and any other toppings you desire, distributing it evenly over the cheese. Cook until cheese melts; about 2 minutes.
Fold. Using a spatula, fold the empty side of the quesadilla over the cheesy side and press down lightly on it. Continue to cook until the cheese fully melts and the tortilla is lightly browned.
HOW TO REHEAT QUESADILLAS If you have leftover quesadillas, you can reheat them. I suggest heating a skillet over medium heat with a pat of butter. Place your quesadilla in it and let it slowly heat up, making sure not to let it burn, until the filling is warmed through. You can also reheat them in the oven by placing the quesadillas on a baking sheet and heating in a 325-degree F oven for 10-15 minutes. Both methods will give you a nice crisp quesadilla.