Do you have five minutes? Great. If not, you should take the time to make 5 minutes for yourself because if you don't, you'll never have homemade Nutella.
I've been following cookbook on twitter for years. In fact, it was probably the first account that I followed. They had a recipe up for homemade nutella. I modified it a bit for what I had on hand.
2 c nuts, roasted (I used dry roasted macadamia nuts with sea salt)
1 1/4 c powdered sugar
1/2 c cocoa powder
1 tsp vanilla extract
1-3 T peanut oil
Add nuts, powdered sugar, cocoa powder, and vanilla extract in a food processor and process until the nuts are small and the powdered sugar + cocoa powder are well mixed. Add in the oil 1 Tbsp at a time. I made the mistake of adding 3 T of oil right away when it looked like the mix was too dry, but if you process long enough, the nuts will release their own oils. Process for ~2-3 minutes and enjoy.
Holy crap, it's a blog post about food and not science. Amazing. :)