Cook sausages according to package directions; cut them into 1/4-inch slices; set aside. In a skillet, sauté onion and bell pepper in oil until almost tender. Stir in garlic and chili powder; cook for 1 additional minute. Next, add sausage and chiles; set aside.
In a bowl, combine cheeses, green onion, and cilantro. In a greased, 13-by-9-by2-inch baking dish, sprinkle one third of tortilla chips. Follow with one-half of the sausage mixture and one-half of the cheese mixture; repeat. In a bowl, beat eggs, milk, salt and pepper sauce; pour over layered ingredients.
Sprinkle with remaining tortilla chips. Bake, uncovered, at 350 degrees F for 45-50 minutes or until a knife inserted in the center comes out clean. Let stand for 10 minutes before cutting.