Saute sausage in pan until cooked, break up into chunks, not small pieces. When completely cooked, pour meat in to a pan lined with paper towels, and let all of the excess grease drip out of the pan without wiping out the pan.Press the meat with paper towel to absorb grease. Set aside meat.Using the same pan, sauté the chopped onion in the remaining drippings from the sausage. Pour the onions on top of the meat.In large bowl or blender, beat the eggs. Add milk and seasonings to eggs.Butter all of the bread on one side (optional), cut or tear into pieces and lay into a greased 9x13 pan.Layer the cooked sausage, onion and green chiles on top of the bread.Top with the grated cheese.Pour the seasoned eggs over all.If you like a little color and flavor, top with salsa (about ½ cup) drizzled over cheese.Cover casserole with foil or plastic wrap and place in refrigerator overnight, or at least 1 hour.Bake uncovered at 300 degrees for 1 hour, until puffed and golden brown.Serve with salsa and sour cream.