Combine milk and 2 tbls Nutella in a bowl and mix until combined and smooth. Stir in oats until completely coated in milk mixture.
In the bottom of each mason jar, add one tablespoon Nutella. Divide oat mixture equally into 2 pint sized mason jars and pour any leftover milk over the oats and add the lid and ring to mason jar. Let sit in refrigerator overnight (at least 8 hours).
Top with crushed granola bars and a drizzle of Nutella. Enjoy this breakfast cold or remove lid and ring and microwave for 1-2 minutes to gently warm.