Preheat oven to 350°. In a greased 13x9-in. baking dish, layer half the potatoes, all the chiles, all the salsa, half the sausage and half the cheese. Repeat layers with remaining potatoes, sausage and cheese.
Beat eggs and milk; add cumin, salt and pepper. Pour over potato mixture.
Bake, uncovered, until eggs are set in center, 35-40 minutes. Let stand 15 minutes. If desired, serve with warm tortillas, sour cream and additional salsa.
