I live and work close to the Nalen Restaurant and eat there once or twice per week, on average. I recommend it strongly and without hesitation for visitors to Stockholm, both for lunch and dinner. The food is of high quality. The cuisine features modern Swedish dishes, using fresh products and ingredients in innovative ways. Hence, it is a splendid way to acquaint oneself with the culinary tradition of the country, but without ending up in "routine" cooking. Among the main dishes, I especially recommend the reindeer, the meatballs and the Biff Rydberg (a Swedish classic). Furthermore, the staff is very service-minded, professional and friendly, which adds to the eating experience. The location is quite central but not on a big street, which means that big, "touristy" groups generally don't find their ways here, which makes for a somber and pleasant eating experience. Lastly, for the quality of food here, the prices are very reasonable: among the highest quality/price ratios in Stockholm.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.