There are plenty of recipes you can use nut, soy or rice milk in, but for this one it's best to stick with full-fat dairy milk. The reason for this is alcohol already makes the pudding more runny (the same reason you can't add too much of it to jello desserts) and a water-based milk alternative would make it even more so. Feel free to experiment if you want, and you can also swap the Cool Whip for a dairy-free alternative. But I haven't tried either of those changes so if you do, let me know how your drunken worm cups dessert comes out! Even if it's a bit runny, you can serve them up as 'dessert cocktails' rather than set desserts. All the flavour will be in there either way!