Place ricotta cheese in a fine mesh sieve set over a bowl. Let it drain for 10 minutes to remove excess moisture, then discard the liquid.
In a medium bowl, beat the drained ricotta and mascarpone together with a hand mixer until smooth and creamy, about 2 minutes.
Add powdered erythritol, vanilla extract, cinnamon, and orange zest. Beat until light and fluffy, about 1 more minute.
Gently fold in 2 tablespoons of the sugar-free mini chocolate chips with a spatula.
Spoon the cannoli cream into 4 small serving cups or glasses. Top each with the remaining chocolate chips and a sprinkle of chopped pistachios. Refrigerate for at least 30 minutes before serving to let the flavors meld.
