Preheat the oven to 400 degrees F (200 degrees C).
Chop the White Onion (1).
Drain the Canned French Style Green Beans (14 ounce), Canned Corn (15 ounce) and Water Chestnuts (8 ounce).
In a 9-inch casserole pan, layer the green beans, corn, water chestnuts and chopped white onion.
In a small bowl, mix together Sour Cream (1 cup) and Cream of Chicken Soup (10.5 ounce). Spread mixture over casserole.
Melt the Unsalted Butter (1/2 cup).
Top casserole with Monterey Jack Cheese (1 1/2 cup), Crackers (1 1/2 cup), and melted butter. Cover with foil and bake for 40 minutes. Remove the tin foil in the last 10 minutes and cook until lightly browned and bubbling.