Place the chicken breasts in the bottom of a slow cooker and cover with enchilada sauce. Cook on low for 6-8 hours.
Shred chicken breasts.
Pour some enchilada sauce along the bottom of a casserole dish.
Cut corn tortillas in quarter-size pieces (I use a pizza cutter to do this). Place a layer of corn tortillas along the bottom, cover with the sauce and chicken mixture, and then add cheese. Continue layering until you have used all of your tortillas and cheese.
Bake at 350 degrees for 15-20 minutes until the cheese is bubbly. When you remove it from the oven, allow it to set for about 5 minutes and then cut and serve.
Recipe by Melissas Bargains at http://www.melissasbargains.com/easy-chicken-enchilada-casserole-recipe/