Preheat the oven to 375°F. In a large bowl, stir together the shredded chicken, black beans, cumin, and chili powder until evenly mixed.
Spread 1/2 cup of enchilada sauce across the bottom of a 9x13-inch baking dish.
Scatter half the torn tortillas over the sauce, followed by half the chicken and bean mixture, another 1/2 cup of sauce, and 1 cup of cheese. Repeat the layers once more, ending with the remaining cheese on top.
Bake for 25 minutes, or until the cheese is fully melted and the edges are bubbling.
Remove from the oven and sprinkle the green onions over the top before serving.