Preheat the oven to 350 degrees.
Mix together the ingredients for the crust until well combined.
Press the crust mixture into the bottom of a well greased 9x9 baking dish.
Bake for 8 minutes, and allow to cool.
Place the heavy whipping cream and ⅓ cup Swerve into a pot over medium low heat.
Bring the mixture just to a boil, and then reduce the heat to low.
Simmer uncovered for 30 minutes, or until the mixture is the consistency of condensed milk.
Remove from the heat, and stir in the pumpkin puree, butter and xanthan gum. Allow the mixture to cool to room temperature.
Pour the filling over the crust, and top with the chocolate chips, coconut flakes and walnuts.
Bake for 20-25 minutes until set and cooked through.
Allow the mixture to cool completely before serving.