Preheat the oven. Set your oven to 375°F (190°C). Lightly oil a 9x13-inch baking dish or coat it with a thin layer of enchilada sauce.
Warm the aromatics. Heat olive oil in a skillet over medium heat. Add the diced onion and a pinch of salt.
Cook 3–4 minutes until softened, then stir in garlic for 30 seconds until fragrant.
Season the filling. Add cumin, chili powder, and smoked paprika to the onions. Stir for 30 seconds to bloom the spices.
Combine chicken and beans. Add shredded chicken and black beans to the skillet. Stir to coat with the spices.
Pour in 1/2 cup of the enchilada sauce to moisten. Season with salt and pepper. Turn off the heat and let it cool slightly.
Prep tortillas. To prevent tearing, warm tortillas.
Wrap them in a damp paper towel and microwave for 30–45 seconds, or briefly heat them in a dry skillet.
Assemble the enchiladas. Spread about 1/2 cup enchilada sauce over the bottom of your baking dish. Place a warm tortilla on a flat surface, add 1/3 to 1/2 cup of the chicken-bean mixture, and sprinkle a little cheese. Roll snugly and place seam-side down in the dish.
Repeat with remaining tortillas.
Sauce and cheese. Pour the remaining enchilada sauce evenly over the rolled tortillas. Sprinkle the rest of the cheese across the top.
Bake. Cover with foil and bake for 15 minutes. Remove foil and bake another 8–10 minutes, until the cheese is melted and bubbly with lightly crisp edges.
Rest and garnish. Let the enchiladas rest for 5–10 minutes.
Top with chopped cilantro, green onions, and a squeeze of lime. Serve with a dollop of Greek yogurt or light sour cream if you like.