Begin by pouring the enchilada sauce into your slow cooker and spreading it evenly across the bottom.
Add a layer of shredded cooked chicken over the sauce, spreading it out smoothly so every bite gets some flavorful meat.
Sprinkle half of the diced onion and spices (cumin and chili powder) evenly over the chicken for a fragrant, smoky aroma.
Repeat the layers with remaining chicken, onions, spices, and finish with a generous pour of enchilada sauce and half of the cheeses on top.
Cover the slow cooker and cook on low for about 4 to 6 hours, until the chicken is tender and the sauce is bubbling with fragrant spices filling your kitchen.
Preheat your oven to 190°C (375°F). Carefully transfer the cooked chicken mixture into a baking dish, spreading it out evenly.
Layer the tortillas over the filling, pressing gently to cover as much as possible, then sprinkle with the remaining cheese for a bubbly, golden crust.
Bake uncovered for 15–20 minutes, until the cheese is melted, bubbling, and just starting to turn golden around the edges. Your kitchen will be filled with the irresistible smell of cheesy, smoky goodness.
Remove from the oven and let rest for 5 minutes—this helps everything set so you can slice cleanly without the filling spilling out.
Slice into squares and serve hot, garnished with chopped cilantro, sour cream, or sliced jalapeños if desired. Enjoy the gooey, cheesy, smoky flavors with every bite!