Preheat the oven to 375°F (190°C) and lightly spray an 8×8 baking dish with nonstick spray.
Heat 1 tablespoon olive oil in a skillet over medium heat, then add the chopped sweet onion and chopped red pepper and sauté until softened, about 5–6 minutes.
Add the shredded cooked chicken, 1 teaspoon cumin, 1 teaspoon chili powder, 1 teaspoon smoked paprika, a pinch of cayenne, and a pinch of salt and pepper to the skillet; stir to combine and heat through.
Pour in half of the enchilada sauce (about 1 can) and add the black beans and 1 cup of shredded cheese; stir until everything is evenly coated and warmed.
Place two corn tortillas side by side in the prepared baking dish, spread a portion of the chicken mixture over them, then repeat layering tortillas and filling until all tortillas and filling are used.
Top the assembled casserole with the remaining 1 cup of shredded cheese and drizzle the remaining enchilada sauce over the top.
Bake uncovered for 25–30 minutes, until the cheese is melted and bubbly; remove from the oven and sprinkle with cilantro before serving.