1. Arrange bread cubes in an 11 x 7-inch baking dish coated with cooking spray.
2. Coat a large nonstick skillet with cooking spray; place skillet over medium-high heat until hot. Add sausage and green onions; cook until sausage is browned, stirring until it crumbles. Drain sausage mixture, if necessary. Layer sausage mixture and cheese over bread cubes.
3. Combine milk and remaining 4 ingredients; pour over bread mixture. Press down on bread mixture with a spatula to cover totally with milk mixture. Cover and chill 8 hours or overnight.
4. Preheat oven to 350°.
5. Bake casserole, uncovered, at 350° for 30 minutes or until set and lightly browned. Let stand 5 minutes before serving.