Preheat the oven: Set to 375°F (190°C).
Lightly oil a 9x13-inch baking dish.
Cook the aromatics: Heat olive oil in a large skillet over medium. Add onion with a pinch of salt and cook 4–5 minutes until translucent. Stir in garlic and cook 30 seconds, just until fragrant.
Brown the chicken: Add ground chicken.
Season with salt, pepper, chili powder, cumin, smoked paprika, and oregano. Cook, breaking up the meat, until no pink remains, about 5–7 minutes.
Build the saucey filling: Stir in tomato paste (if using), then add enchilada sauce and broth. Bring to a gentle simmer and cook 2–3 minutes to marry the flavors.
Taste and adjust seasoning.
Add beans and corn: Fold in black beans and corn. Turn off the heat. You want a slightly saucy mixture—it shouldn’t be dry.
Prep the tortillas: If using corn tortillas, stack and cut into halves or quarters for easier layering.
This helps them sit evenly in the dish.
Layer the casserole: Spoon a thin layer of sauce from the skillet into the baking dish. Add a layer of tortillas to cover. Top with a third of the chicken mixture and a third of the cheese.
Repeat for two more layers, finishing with cheese on top. Aim for 3 layers total.
Bake: Cover with foil and bake 15 minutes. Uncover and bake another 10–12 minutes, until the cheese is melted and bubbling and the edges are lightly crisp.
Rest and garnish: Let the casserole rest 10 minutes to set.
Garnish with chopped cilantro. Add your favorite toppings—sour cream, avocado, jalapeños, or a squeeze of lime.
Serve: Slice into squares and serve warm. It pairs well with a simple green salad or cilantro-lime rice.