Preheat oven to 450 degrees. Spray a large sheet pan with non-stick cooking spray.

Arrange 1 tortilla at each end of the sheet pan so that half of the tortilla is on the pan and half is hanging over the edge. Arrange two tortillas on each long side of the sheet pan in the same manner. You should have 6 slightly overlapping tortillas draped along all the edges of the entire sheet pan.

Place one tortilla directly in the center of the pan. The pan should be completely covered. Sprinkle half of the cheese over the tortilla layer in the pan.

Combine the chicken, taco seasoning and diced chilies in a large bowl. Spread the chicken mixture evenly over the cheese layer. Top the chicken evenly with the remaining cheese.

Place a tortilla in the center of the sheet pan, over the toppings. Fold over the tortillas along the edges so they overlap the tortilla in the center. The entire pan should now be filled with on large, rectangular quesadilla.

Spray the top of the quesadilla with non stick cooking spray. Place a second sheet pan over the quesadilla and press down gently. Leaving the second sheet pan on top, bake for 20-25 minutes or until the quesadilla is golden brown and slightly crispy.

Cut the quesadilla into squares and serve with your favorite taco toppings--sour cream, salsa, guacamole, etc.