Preheat the oven to 325 degrees. Grease a 9x5 inch loaf pan.
In a medium bowl, whisk the flour, baking soda, salt, and cinnamon to combine.
In a large bowl, whisk the butter and sugar to combine. Add the eggs one at a time, then beat in the vanilla, bananas, and yogurt.
Add the flour mixture and to the banana mixture and mix just until combined.
Fold in the cocoa nibs. Pour ½ the batter into the prepared pan, and top with ½ of the nutella. Pour the remaining ½ of the batter on top, and finish with the last of the nutella. Use a wooden skewer, chopstick, or a knife to swirl the nutella into the batter.
Bake until the loaf is golden brown and pulls slightly away from the edges of the pan, and a toothpick inserted into the center comes out with just a few moist crumbs.
Cool the loaf in the pan for 15 minutes, then invert onto a cooling rack and cool completely.