Prepare the Slow Cooker:

1. Lightly grease the liner of the slow cooker with nonstick cooking spray.

2. Layer the Ingredients:

1. Place the chicken breasts into the bottom of the slow cooker.
2. Sprinkle the taco seasoning, salt, and black pepper over the chicken.
3. Pour the enchilada sauce and drained tomatoes over the chicken.

3. Slow Cook the Chicken:

1. Cover the slow cooker and cook on low for 4 to 5 hours, or until the chicken is cooked through.

4. Shred the Chicken and Add Tortillas:

1. Shred the chicken with two forks.
2. Stir the tortilla wedges and half of the cheese into the chicken.

5. Layer and Cook:

1. Press the casserole into an even layer and top with the remaining cheese.
2. Re-cover the slow cooker and continue cooking for 30 minutes, or until the cheese is melted and bubbly.