Soak Medjool dates in hot water for a few minutes. Drain, and reserve water.
Fine grind walnuts in coffee grinder or food processor.
Add ground walnuts, dates, cacao powder, coconut flour, salt, and vanilla into a food processor and process on high for about a minute until dough is formed.
Check texture by pinching the dough between your fingers. It should be sticky and able to keep its shape. If the mixture is too dry, add more water in which you have soaked the dates.
Add cacao nibs and pulse a few more times.
Using a tablespoon, scoop out dough and roll between your palms to form your balls. Roll in cacao powder.
Store in an airtight container in the refrigerator for up to 2 weeks. Place in zip-lock bags and freeze up to 3 months. You don't need to thaw brownie bites before serving. As a measure, I used a US cup (240ml).