Place all ingredients except the fruit into a meal prep jar or similar container. Still until combined. Top with frozen fruit, cover, and refrigerate overnight, or at least 4 hours until set.
1/4 cup Greek yogurt, 1/3 cup milk, 1 scoop protein powder, 1/4 cup old-fashioned oats, 1 tablespoon chia seeds, 1 tablespoon ground flax seed, 1/2 cup frozen fruit
Once ready to eat, stir the thawed fruit and its juices into the overnight oats and enjoy.