01 - In a medium bowl or jar, mix rolled oats, milk, Greek yogurt, chia seeds, and honey or maple syrup until well combined.
02 - Add chopped walnuts, almonds, and pumpkin seeds to the mixture, stirring thoroughly to ensure even distribution.
03 - Gently fold in half of the mixed berries and sliced banana, reserving the remaining fruit for topping.
04 - Cover the container and refrigerate for at least 8 hours to allow ingredients to meld and soften.
05 - In the morning, stir the oats mixture; add a splash of milk if a creamier consistency is desired.
06 - Top with the reserved berries and banana slices, drizzle nut butter and additional honey or maple syrup if preferred, then serve chilled.