Preheat oven to 350°F. Line a baking sheet with parchment paper.
In a large bowl, combine oats, nuts, and seeds.
In a small bowl, whisk together coconut oil, honey or maple syrup, vanilla extract, cinnamon, salt and cocoa powder (if using). Pour over oat mixture and stir until everything is evenly coated.
Spread the granola onto the prepared baking sheet in an even layer.
Bake for 20 minutes. Remove from oven and stir. Bake for an additional 10 minutes until golden brown.
Remove from oven and let cool completely before stirring in the chocolate chunks. Store in an airtight container at room temperature for up to 1 month.