Preheat grill to medium-high heat. Marinate the steak with 2 tablespoons of the lime juice, ancho powder, and salt for 30 minutes. Toss the onion and corn in olive oil. Grill onion until tender, corn until golden brown, and steak to rare. Cut steak into 3/4-inch pieces, chop onion, cut kernels from the cob, and transfer all to a large bowl. Preheat oven to 400 degrees F. Toss beans, both peppers, chicken broth, remaining lime juice, and lime zest with the steak. Place 2 tortillas in the bottom of a 9-inch by 13-inch casserole dish and sprinkle with 3/4 cup of the cheese. Spoon 1/3 of the steak and bean mixture evenly over the cheese and top with 1/3 of the tomato slices and 1/2 teaspoon of oregano. Repeat to complete 3 layers, cover with aluminum foil, and bake for 20 minutes. Bake, uncovered, for 10 more minutes. Serve immediately.