01 - In a medium bowl, combine the shredded chicken, corn, diced tomatoes, and chopped onion until evenly mixed.
02 - Lay two tortillas flat and sprinkle half the cheese evenly over each tortilla. Distribute the chicken and vegetable mixture evenly, then top with remaining cheese and place a second tortilla on top of each.
03 - Warm a large nonstick skillet over medium heat. Place assembled quesadilla in skillet and cook for 2–3 minutes per side, pressing gently, until golden brown and cheese is melted.
04 - Remove from skillet, let rest 1 minute, then cut into wedges. Serve hot with salsa or toppings of choice.