Preheat the oven to 450˚.
Melt the butter in a 10-inch cast-iron skillet over medium-high heat.
Add the garlic, tomatoes and onion and season with the chili powder, cumin and salt. Cook until the onion is softened, 2 to 3 minutes.
Add the beans, enchilada sauce and chicken, then stir to combine.
Remove from the heat, gently fold in the quartered tortillas and top with the cheese.
Transfer the skillet to the oven and bake until the cheese melts, 12 to 15 minutes.
Let cool for 10 minutes.
Top with sour cream, cilantro, olives and avocado.
Serve with lime wedges.