Heat oven to 400° F. Heat the oil in a large skillet over medium-high heat. Add the onion and poblano. Cook, tossing often, until the onion is browned, 5 to 7 minutes. Add the mushrooms and cumin. Cook, tossing frequently, until the mushrooms are browned and tender, 4 to 6 minutes. Remove from heat. Add the beans, 4 ounces of the cheese, and ¼ teaspoon each salt and pepper.
Spread ½ cup of the enchilada sauce in the bottom of a 9-by-13-inch baking dish. Roll up the filling in the tortillas, dividing evenly (about ⅓ cup per tortilla), and place seam-side down in the dish.
Top with the remaining enchilada sauce and the remaining 4 ounces of cheese. Bake, uncovered, until the sauce is bubbling and the cheese is melted, 14 to 16 minutes. Serve topped with the cilantro.
Made these last night. They were fantastic. Full of flavor & easy to put together. We'll definitely add this to our rotation.