Add all ingredients to the Ninja Creami pint container.
Blend using an immersion blender. If you don't have an immersion blender you can also use a whisk or handheld masher to mash the banana as thoroughly as possible, and then mix.
Put the lid on and freeze for 24 hours.
Remove from the freezer and place the container in the Ninja Creami Machine. Press the Lite Ice Cream button.
Press re-spin one time. At this point, the ice cream should be nice and creamy. If it looks too crumbly, press re-spin an additional time.