Line a baking sheet with parchment paper. Set aside.
To a medium bowl, add softened butter and confectioners' sugar. Using a hand mixer on low speed, mix until combined.
Add the chopped pecans and bourbon to the butter mixture. Mix thoroughly until well combined.
Using a 1 ½-tablespoon scoop, portion the mixture onto the lined baking sheet.
Place the bourbon balls in the refrigerator for about 30 minutes. After 30 minutes, remove the bourbon balls from the refrigerator and roll each into a ball shape. (If the mixture still seems too dry, add a bit more bourbon or a teaspoon of corn syrup.)
Cover the balls with plastic wrap and place the truffles back into the refrigerator for an additional 30 minutes, up to overnight, to chill.
When ready to coat, add chocolate chips and vegetable oil to a microwave-safe bowl. Heat in 20-second increments, stirring after each session, until the chocolate is melted and smooth. Let the melted chocolate cool slightly, about 2 to 2 ½ minutes, before dipping the bourbon balls.
Line another baking sheet with parchment paper.
Remove bourbon balls from the refrigerator. Drop each into the melted chocolate, ensuring it is fully coated.
Using a fork, lift each bourbon ball from the chocolate. Gently slide it onto the newly lined parchment-lined baking sheet using a second fork or a toothpick. If the chocolate begins to thicken, reheat briefly in the microwave to maintain a smooth consistency.
If desired, drizzle each bourbon ball with extra melted chocolate. For an optional garnish, roll in sprinkles or crushed pecans.
Place the coated bourbon balls in the refrigerator for about 30 minutes, or until the chocolate has fully set.