Place oats, matcha powder and blueberries in large bowl; stir to combine. Place cashews in food processor or blender; process until finely ground. Stir into oat mixture. Add agave nectar (or honey) and stir to combine well. Add water, a small amount at a time, until oat mixture is moist enough to form into balls. Shape into 24 (about 1-inch diameter) balls. Roll lightly in chopped pistachios. Refrigerate, covered, until chilled. Store leftovers in refrigerator, covered.