Line a small plate or dish with parchment paper. Set aside.
Mix dry ingredients together, adding marshmallows and chocolate chips last. Mix well.
Slowly add almond milk or liquid, stirring in gradually. You'll think you need more milk but aim for as little milk as possible. The mixture may almost look crumbly. That's ideal for forming into balls.
When the mixture is evenly mixed, form into balls using your hands and roll between your palms to smooth. If your mixture is too crumbly, add 1 tsp of liquid at a time. If it's too moist to form into balls, add more protein powder or oats. (If you double this recipe, which I recommend, you may want to rinse your hands half way through. The more balls you form, the more the other balls will stick to residue on your hands.)
Add balls to parchment paper and place in the freezer for 10-15 minutes. Store leftover balls in the freezer and thaw for 5-10 minutes before eating.