In a mixing bowl, combine ricotta cheese, confectioners' sugar, cinnamon, nutmeg, and vanilla extract. Mix until smooth.
Fold in the mini chocolate chips and chopped pistachios.
Pour the mixture into the pre-baked and cooled pie crust. Smooth the top with a spatula.
In a separate bowl, whip the heavy cream with granulated sugar until stiff peaks form.
Spread the whipped cream over the cannoli mixture in the pie crust.
Refrigerate the pie for at least 3 hours before serving.
Optional: garnish with additional chocolate chips and chopped pistachios before serving.