Be sure to strain the liquid from the ricotta using cheesecloth otherwise, the dip can be runny. Place several layers of cheesecloth in a strainer and add the ricotta. Let drain for at least 20 minutes before squeezing by hand to remove the excess liquid. This can take a bit of time, but it's worth it to get a better consistency!
Add the strained ricotta, mascarpone, powdered sugar, vanilla extract, and orange zest to a mixing bowl. Beat with a paddle until just combined.
Mix in the chocolate chips and, if desired, the chopped pistachios. Transfer to a serving bowl and sprinkle a few more mini chocolate chips and pistachios on top. Chill until ready to serve.
Serve with cannoli shells or chips, waffle cones, or graham crackers.