In a medium-sized bowl or mason jar, combine old-fashioned oats, chia seeds, and cocoa powder. Stir well until evenly blended, creating a base.

Pour in your preferred milk and add Greek yogurt along with maple syrup. Stir thoroughly until creamy and all ingredients are well combined.

Gently fold in crushed Oreos and mini chocolate chips into your oat mixture. Mix until evenly distributed.

Cover and place it in the refrigerator. Allow the mixture to chill for at least 5 hours or overnight.

In the morning, stir the oats well. Adjust with more milk if too thick, and top with more crushed Oreos and mini chocolate chips before serving.