Start by carefully removing the skin from your bone-in chicken breasts. Pat the chicken dry, then rub evenly with garlic powder, cumin, chili powder, salt, and black pepper.
Pour half of the red enchilada sauce into the bottom of your slow cooker. Place the seasoned chicken breasts on top, then spoon over the green chile peppers. Pour the remaining enchilada sauce over the chicken and chiles, ensuring everything is well coated. Cover and cook on low for 5-6 hours or until the chicken is tender and shreds easily.
Once cooked, remove the chicken breasts from the slow cooker and shred the meat using two forks or tongs, discarding bones. Return the shredded chicken to the slow cooker and mix it with the sauce and chiles for a cohesive filling.
Start layering your enchilada pie right in the slow cooker or a separate baking dish if your slow cooker insert isn’t oven-safe. Place a tortilla on the bottom, then spread a portion of the chicken mixture, followed by a sprinkle of shredded cheddar cheese and a dollop of sour cream. Repeat layers until all ingredients are used, finishing with a generous layer of cheese on top.
Cover and cook on low for an additional 30-60 minutes to melt the cheese and meld the flavors together. Alternatively, if using an oven-safe dish, bake at 350°F for 20 minutes until bubbly and golden on top.
Let the pie rest for a few minutes before slicing. Serve warm with your favorite toppings like fresh cilantro, avocado slices, or a squeeze of lime for an extra pop of brightness.