In a small bowl, pour ½ cup of whisky over the pecans. Cover and soak the pecans overnight.
Spread out the pecans on a cookie sheet and bake at 352 F until lightly toasted. Let them cool and then chop finely.
Process the vanilla wafers in a food processor until they are crumbled. Add in the cocoa, powdered sugar, syrup, ¼ cup whisky, and pecans and process until combined. Use a 1 tablespoon cookie scoop to measure out the balls.
Roll the whisky balls smooth and roll into chocolate jimmies. If the balls are a little "wet" feeling, just refrigerate to dry.