Cook the frozen Brussels sprouts in plenty of boiling salted water for about 10 minutes at medium heat. In the meantime, roughly chop the walnut kernels and roast them in a large pan without fat, remove and let them cool down.
Heat the oil in a frying pan. Fry the gnocchi over medium heat while turning for about 12 minutes. Drain the Brussels sprouts, quench and drain. Depending on size, halve if necessary. Add the sprouts to the gnocchi and fry for approx. 5 minutes.
Grate the cheese roughly. Season gnocchi pan with salt, pepper and nutmeg. Fold in half of the cheese and nuts, sprinkle the rest on top and serve.