Trim crusts from bread; reserve crusts for another use. Cut bread into 1/2-inch cubes.
Arrange half of bread cubes in an 8-inch square baking dish coated with vegetable cooking spray. Combine chicken and next 6 ingredients, and stir well. Spoon chicken mixture over bread cubes in baking dish. Top with remaining bread cubes.
Combine milk and egg substitute; stir well. Pour mixture over bread cubes. Cover and chill 8 hours.
Bake, uncovered, at 350° for 55 minutes; sprinkle with Cheddar cheese. Bake 5 additional minutes or until cheese melts. Let stand 10 minutes before serving.