Preheat your oven to 350°F (175°C). Place the chicken breast filets in a covered dish and bake for 35-45 minutes until the juices run clear and the chicken is fully cooked.

In a large mixing bowl, combine the shredded chicken, garlic powder, cumin, chili powder, black pepper, and diced jalapenos if using. Pour in ½ cup of enchilada sauce and ½ cup of sour cream, then add 1 cup of reduced-fat cheddar cheese. Stir everything together until the chicken is evenly coated.

Take your whole-grain tortillas and fill each one with about ½ cup of the chicken filling mixture. Roll them up tightly and arrange the enchiladas in your slow cooker.

In a separate bowl, mix the remaining enchilada sauce with ½ cup of sour cream and pour this sauce mixture evenly over the rolled enchiladas.

Cover your slow cooker with its lid and set it to cook on low for 3-4 hours.

Once cooked, serve warm, garnished with additional cheddar cheese, diced tomatoes, and shredded lettuce if desired.