Add the oatmilk, soymilk, ripe/overripe banana, and protein powder to a blender.
Blend for a few seconds until all ice cream ingredients are well combined.
Pour the ice cream mixture into your plastic Ninja Creami pint container.
Pop the lid on the Creami pint and place the mixture in the freezer for 24 hours.
When you're ready to make your ice cream, remove the pint from the freezer and flatten out any bumps with a spoon.
Spin the ice cream pint once on the "lite ice cream" setting.
Chop the chocolate peanut butter cups into small pieces and add them to the center of the ice cream pint (or use them as a topping for your ice cream).
Add a splash of non-dairy milk to the container, then spin the ice cream again using the "mix-in" setting.
Add a bit more non-dairy milk and spin the ice cream one final time using the "re-spin" setting.
Drizzle the peanut butter on top of your ice cream.
Dig in and enjoy your delicious, sweet, and creamy ice cream!