In a wide-mouth mason jar or airtight container, whisk together the rolled oats, chocolate protein powder, cocoa powder, chia seeds, and sea salt until well combined.
Add the almond milk, Greek yogurt, and maple syrup to the dry mixture.
Vigorously stir the contents for at least 60 seconds to ensure the protein powder is fully hydrated and no clumps remain.
Fold in the dark chocolate mini chips.
Seal the container with a lid and refrigerate for a minimum of 4 hours, or ideally overnight (8 hours), to allow the oats and chia seeds to absorb the liquid.
Before serving, remove the lid and stir thoroughly. If the consistency is too thick, incorporate an additional tablespoon of almond milk.
Garnish with extra chocolate chips or a dollop of yogurt if desired and serve chilled.