Preheat oven to 350 degrees and grease a 9" x 9" pan.
Stir the brownie mix, pumpkin nog, vegetable oil, and eggs together in a medium mixing bowl until combined.
Spread brownie batter evenly into pan. Bake 20-25 minutes, or until a toothpick comes out clean from center of brownies.
Allow the brownies to cool completely. Once cool, add the chocolate chips to a bowl.
Then, add the heavy cream and 1/3 cup pumpkin nog to a small pot. Heat over medium heat just until it reaches a boil.
Pour over the chocolate chips and allow to sit 3-5 minutes. Then, stir until smooth.
Spread the mixture over the top of the brownies and allow the ganache to set completely at room temperature or in the fridge.
Then, cut into squares and serve.