Mash the pumpkin pie in a mixing bowl until the crust and filling are fully incorporated. Using about 1 tablespoon per ball, form into balls. Freeze for 30 minutes.

Line a baking sheet or plate with parchment paper.

Melt chocolate chips in the microwave until almost all the chips are melted, about 1 minute. Stir until smooth and glossy. Roll the balls in the chocolate until fully covered. Place on parchment paper. Immediately sprinkle with walnuts and refrigerate for at least 15 minutes or until the chocolate hardens.