Prepare pudding mix in a mixer, add the mix and 2 cups of milk. If you are lactose intolerant, water also works. When pudding is set up (about 10 minutes in the Fridge) begin putting it together. Layer cookies on the bottom of a 9×13 or a 9×9 dish, then layer half of the pudding mix over the cookies, then place 1/2 of the bananas on top of the pudding, repeat the layers again with cookies, pudding and bananas. Then cover with the cool whip and crushed nilla cookies. Cool in the Fridge for at least a hour, store in the fridge.