If using raw chicken, cook it through, then let it cool slightly before chopping or shredding.
Optional: Heat a lightly oiled skillet over medium heat and sauté the diced red peppers and corn for 2 to 3 minutes, until lightly softened and any excess moisture has cooked off. Remove from the skillet and set aside.
In a small bowl, combine the cooked chicken with the barbecue sauce. Stirring until it is fully coated.
Place one tortilla flat in a large skillet. Sprinkle an even layer of cheese over one half of the tortilla. Top the cheese with a portion of the BBQ chicken mixutre, spreading it in an even layer. Add the red peppers, corn, and red onions over the chicken, then finish with a second layer of shredded cheese. Fold the empty half of the tortilla over the filling and press down gently.
Cook for 2 to 3 minutes over medium-low heat, or until the bottom is golden brown and crisp. Carefully flip the quesadilla and cook for another 2 to 3 minutes, until the second side is golden and the cheese has melted completely.
Transfer the quesadilla to a cutting board and let it rest for a few minutes before slicing.
Repeat with the remaining tortillas and filling.
Cut each quesadilla into three wedges and serve warm with sour cream, ranch, guacamole, salsa, and queso cheese sauce for dipping.
Cheese: Any kind of shredded cheese works well for quesadillas, I prefer Monterey Jack for its meltability, but mozzarella, Colby Jack, and cheddar all work.
Optional Add-ins: Add mushrooms, fresh herbs, black beans, or zucchini to bulk up the quesadillas, just be careful of overfilling them. Make the quesadillas spicy by adding buffalo sauce, add bacon, or use crispy tofu.
Do not overfill the tortilla, it will make flipping your quesadilla very challenging.
Flip the quesadilla on its seam side. Use a spatula or turner under the quesadilla at the open side, gently rolling it onto the other side.
Keep the heat low. Tortillas burn very easily in a dry pan, keep the heat medium-low and keep an eye on the tortillas as they toast.
Store leftover quesadillas in an airtight container for up to three days in the fridge.