Prepare a 8 X 11 inch dish with vegetable spray. Mix meat and pasta well in dish. Dish will nearly be filled. Add in cans of tomato soup and tomatoes with chilies. Mix in, making sure to coat meat/pasta lightly with soup by stirring gently, but well. Shred the stick of mozarella string cheese and tear in to small bits, scattering over top of mixture. (This cheese will melt down through the mixture.) Sprinkle cheddar cheese over top of string cheese bits.