Place the vanilla wafers in the bowl of a food processor or in a zip-top bag. Process or crush with a rolling pin until the wafers are fine crumbs.
Place the chocolate chips in a large microwave-safe bowl. Microwave in 30 second increments, stirring in between, until melted.
Stir in the sugar, rum, and corn syrup. Fold in the vanilla wafers and nuts. Refrigerate for 30 minutes.
Shape into 1 inch balls. Roll in granulated sugar.
Store in an airtight container.
You can taste the rum, so make sure you use a white rum that you like! It doesn't not have to be expensive. I used Bacardi, which was $10–$12 for the whole bottle. Do not use spiced rum. If you don't have rum, you can substitute bourbon. Make sure the vanilla wafers are completely crushed, or nearly so (there can be some little chunks). Having large chunks of wafers will negatively affect the consistency and they will be too wet to roll. You can leave out the nuts, if you prefer. Keep the rest of the recipe the same. It will yield fewer rum balls. You can also roll rum balls in powdered sugar, cocoa powder, chocolate sprinkles, or very finely chopped coconut. Each rum ball contains approximately ⅓ TEASPOON of rum (if you're wondering about alcohol content!). Store the finished rum balls in a covered container, either on the countertop or in the refrigerator. They will keep at room temperature for 1–2 weeks and in the refrigerator for up to 1 month. They can also be frozen in a freezer bag for up to 1 month (defrost at room temperature for several hours before serving).