Cook the frozen Brussels sprouts in boiling salted water for 8-10 minutes. Peel and finely dice the onion. Drain the sprouts and let them drain.
In the meantime heat oil in a pan. Fry the potato noodles for about 5 minutes. Add onion and Brussels sprouts and fry for about 2 minutes. Season to taste with salt, pepper and nutmeg.
Dice the cheese and sprinkle over it. Cover and fry for 2-3 minutes until the cheese has melted. Coarsely chop the nuts and sprinkle them on the pasta pan.