Preheat oven to 400 degrees Fahrenheit.
Shred cooked chicken (Check out the section: "What is the best way to shred chicken for quesadillas?" for more info).
Finely dice tomato, jalapeno, and shallot. Shred cheeses, if needed.
In a medium-large bowl add ingredients: chicken, tomato, jalapeno, and shallot, and taco seasoning. Mix well.
Spray sheet pan with cooking spray.
Fold tortillas in half on the pan and arrange in a pattern to bake.
Open each tortilla and add equal amounts of the chicken mixture. This will be about 1/2 c of the chicken mixture, loosely packed.
Fold each tortilla in half again and spray lightly with baking spray.
Bake in the oven for about 15 minutes, or until crispy, and light golden brown.
Allow to cool 3-5 minutes, enjoy!