In a large bowl, combine the crushed vanilla wafers and nuts.
Add the powdered sugar and cocoa powder to the mixture.
Mix well until all dry ingredients are combined.
Pour in the dark rum and vanilla extract.
Stir the mixture until it becomes a thick, sticky dough.
Refrigerate the mixture for about 15 minutes to firm up.
Once chilled, use your hands to form small balls (about 1 inch in diameter).
Roll each ball in chocolate sprinkles to coat.
Place the coated rum balls on a baking sheet lined with parchment paper.
Refrigerate again for at least 30 minutes before serving.