1. Place wafers in a ziplock bag, seal bag and finely crush cookies using a rolling pin.
2. Place chocolate chips in a bowl set over a pan of simmering water (do not let water boil or bowl touch water). Stir occasionally, until chocolate has melted completely. Remove bowl from heat; stir in sugar, corn syrup and rum. Mix well. Stir in wafers and pecans until a dough forms.
3. Line a large, rimmed baking sheet with parchment. Roll a heaping tablespoon of dough into a 1-inch ball, dusting palms of your hands with confectioners' sugar first to prevent balls from sticking. Place balls on baking sheet. Repeat with remaining dough. Roll balls in nonpareils, if desired. Chill until firm, at least 1 hour, then transfer balls to an airtight container. Refrigerate for 2 to 3 days to mellow the flavor. Keep refrigerated in an airtight container until ready to serve (if stacking, place a layer of waxed paper in between).