Tostada Casserole

• 1 1/2 casserole
• 1 onion
• 3/4 coarsely broken
• 1,900 gr bowl
• 450 gr beef (ground)
• 60 ml water
• 60 gr monterey jack cheese
• 6 gr chili powder
• 1 package tomato sauce
• 1 package green chilies