In a mixing bowl or blender, combine the milk, pistachio pudding mix, optional vanilla pudding mix, and vanilla extract.
Blend until the pudding mix is completely dissolved and the mixture is smooth.
Pour the mixture into the Ninja Creami pint container up to the fill line.
Place the container in the freezer and freeze for 24 hours until completely solid.
After freezing, remove the container, place it into the Ninja Creami outer bowl, and attach the paddle lid.
Process on the 'Lite Ice Cream' setting.
If the ice cream is crumbly, add a tablespoon of milk and re-spin until creamy.