Put the chicken breasts and the enchilada sauce in your slow cooker.
Cook on HIGH for 4 hours or LOW for 8 hours.
Shred the chicken with 2 forks right in the slow cooker.
Cut the tortillas in to strips, add to chicken and sauce. Stir.
Add 1 cup of cheese and half the olives into the sauce and chicken mixture. Stir again.
Flatten the mixture.
Add the rest of the cheese and the olives on top.
Cook on low for about 40 - 60 minutes longer.
Top with sour cream (optional)
Can I use green enchilada sauce?If you choose to use green enchilada sauce note that it is runnier than red and you may need to use more tortillas. Can I use flour tortillas?Flour tortillas can be use but the casserole may turn out soggy. I recommend corn tortillas if you have them.