In a medium mixing bowl, combine the crushed vanilla wafers, ground pecans, 1 cup of the powdered sugar and the cocoa powder. Whisk to combine.

In a 1-cup measuring cup, whisk together the corn syrup and bourbon. Add the bourbon mixture to the dry ingredients and fold together using a spatula until all ingredients are combined. It may seem dry at first, but keep mixing, it will all come together.

Place 1 to 2 cups of powdered sugar in a flat bowl or rimmed plate. Roll the dough (firmly) into 1-inch balls (or use a small cookie scoop), then immediately roll in the powdered sugar. Place the cookies on a wax paper lined baking sheet. Continue rolling until all cookies are coated in powdered sugar. Set the cookies aside for 1 hour, then roll again in the powdered sugar. Store the bourbon balls in an airtight container in the refrigerator for up to 2 weeks.