Mexican Cheese Blend is just a bag of assorted cheeses tossed with mexican spices. You can get it at most grocery stores.
Feel free to jazz it up more with chopped bacon, jalepenos, minced red or green onions!
You can also use chicken breast if you are not a fan of chicken thighs.
I lightly butter my pan after each quesadilla. It really adds a nice buttery, crunch to the outside of the tortilla.