Add all ingredients to the Ninja Creami container. Stir together to combine.
Cover, then place in the freezer on a level surface and freeze for at least 24 hours.
Run a little warm water on the outside of the Creami container to unfreeze the outside.
Process on the Ice Cream setting. If crumbly, add a splash of milk (about a Tbsp) and respin.
Notes
I used 2 teaspoons of matcha in this recipe. I think it gives the ice cream a nice matcha flavor without being overpowering. I've tried it with a full Tablespoon, and while it's still delicious, it may be too much matcha flavor for some people.
To store leftovers, simply level out the top with a spoon and then place back in the freezer. You will likely need to reprocess before enjoying again.