In a glass jar or airtight container, whisk together the rolled oats, protein powder, chia seeds, cinnamon, ginger, and nutmeg.
Add the finely grated carrots, almond milk, Greek yogurt, and maple syrup to the dry mixture.
Stir vigorously until all components are fully integrated and no dry protein powder clumps remain.
Seal the container with a lid and place in the refrigerator for a minimum of 6 hours, preferably overnight.
Remove from the refrigerator and stir once more; if the mixture is too thick, add a splash of milk to reach desired consistency.
Garnish with chopped walnuts and raisins immediately before serving.