Preheat oven to 350F Lightly spray a loaf pan with cooking spray, then line with parchment paper with long ends. The ends will allow you to lift out the torrone later for slicing.

Put the nuts on a baking sheet and roast for 15 minutes, giving the pan a shake half way through to redistribute the nuts. Let the nuts cool on the pan.

Working in 2 batches, wrap the nuts in a clean kitchen towel and rub them all together to remove the skins. Don't worry if some of the skins remain, just get most of them off. Discard the skins.

Put the chopped chocolate, or chocolate chips, in a large microwave safe bowl and microwave on high for a minute. Stir, and then microwave for an additional 30 seconds. Stir again until all of the chocolate is smooth and glossy. Let the residual heat of the bowl do the final melting. (If for any reason you still have lumps, put the bowl back in the microwave for 15 seconds, until smooth.)

Fold in the Nutella until completely incorporated, and then the nuts. Turn the chocolate mixture into the prepared pan and spread out evenly. I give the pan a few sharp raps on the counter to settle all the chocolate. Let sit until completely hardened. I left mine overnight at room temperature, but you can also refrigerate it.

Use the parchment paper to lift out the torrone. Slice it into slices, mine are just shy of an inch. (If you have refrigerated it and it seems very firm, you can let it sit at room temperature for a while before slicing.)