Preheat the oven to 300°F (149°C).
Put the walnuts, almonds, macadamias, pecans, hemp seeds, chocolate, coconut oil, sweetener and cocoa powder in a large food processor and pulse a few times until well blended.
Spread the mix onto a cookie sheet, cover with parchment paper, and bake for 15 to 20 minutes, until golden brown.
Turn off the oven, and for best results, leave there overnight.
The next day, take out the granola and remove from the cookie sheet with a wooden spatula.
Store in an airtight container for up to 1 week.