Make sure the green beans are thoroughly drained and completely dry-use a towel, if needed. Then place half of the green beans in a casserole dish (a 2- to 3-quart rectangular one works best). Pour 1 can of the soup evenly on top of the layer of green beans. Place half of the sliced water chestnuts over the soup layer. Cover with the remaining green beans and then top with the remaining can of soup. Evenly top with the remaining water chestnuts. Place the dish in the oven and cook for 45 minutes. Top with crushed soy crisps, and return the dish to the oven until chips turn golden brown, another 10 minutes or so. Enjoy!