In a food processor, grind half of the oats until they are a finer consistency. Mix all of the rolled oats and protein powder in a bowl.
Stir in peanut butter, maple syrup, salt, and cinnamon until the mixture is evenly blended.
Mix in the walnuts and mini chocolate chips until just combined.
Use lightly wet hands or a small scoop to shape the mixture into 12 balls, about 1 inch in diameter. If the mixture is too dry, add 1 teaspoon of water at a time until the balls form easily.
Place the balls in an airtight container and refrigerate for 1 hour to firm up before serving.