Melt the chocolate chips over a double boiler, or microwave. Once melted, remove from heat and stir in the hazelnut butter. Whisk well until fully combined. Let it sit 24 hours at room temperature until thick (it should have the consistency of Nutella), or place in the refrigerator 40 minutes.
Dollop about 2 teaspoons of Nutella and place them on a baking sheet lined with parchment paper. Repeat with the remaining Nutella to form 1.5-inch disks. Place the baking sheet in the freezer for at least 30 minutes. In the meantime, prepare the cookie cups.
Preheat oven to 350°F (175°C).
In a large mixing bowl, cream together the coconut sugar, coconut oil, maple syrup, vanilla extract, and almond milk.
Add the brown rice flour, white rice flour, tapioca starch, baking soda, baking powder, and salt. Mix until well combined. Fold in the cacao nibs and mix again. The dough will be slightly crumbly, this is normal.
Press down about 1 tablespoon of dough into a cavity of a silicon muffin pan. Top with a frozen disk of Nutella. Finally, take 1 tablespoon of dough, form a ball and flatten it into a disk between your hands. Place on top of the Nutella disk and press down on the edges to close the cookie cups and trap the Nutella inside. Repeat to fill each muffin cavity.
Bake for 18-20 minutes. Remove from the oven and let it cool 15 minutes at room temperature. Don’t try to remove the cookie cups from the pan or they will crumble. After 15 minutes, transfer the pan to the refrigerator and chill another 15 minutes. Then, you can carefully remove the cookie cups from the pan. The filling should still be melty and the cookie cups chewy on the inside and crispy on the outside.
Keep at room temperature in an airtight container for up to 5 days. The filling will slightly firm up after a few hours. Personally, I think these cookie cups taste even better the next day!