Preheat oven to 350 degrees. Grease a 9x13 casserole dish (preferably glass). You can use a round casserole too, it doesn't really matter. Mix together in pan the tuna, soup and milk. The milk is measured by filling up the soup can that you just emptied out. Gently stir in the peas. Crumble two handfuls of potato chips into the mix and stir gently. Crumble another handful of potato chips over the top. Bake 20 minutes, or until slightly golden brown and bubbling hot. Let stand 5 minutes. Makes 8 servings.