In a large mixing bowl, whip 1 1/2 cups of the heavy cream with the erythritol and vanilla extract until it holds soft peaks. Set the whipped cream aside.
In a separate bowl, whip together the remaining 1/2 cup heavy cream, espresso, and Keto Chow until fully mixed.
Gently fold two thirds of the prepared whipped cream into the Keto Chow mixture, trying to keep as much volume as possible.
Stir the peanut butter into the mixture, allowing some visible streaks to remain in the mousse.
Portion the mousse into four small dishes and top with the remaining whipped cream, sprinkle lightly with pumpkin spice to garnish.
Chill at least 30 minutes for best flavor.
Store well wrapped in the refrigerator for up to three days.