Want a stuffed puffin? Then you're in luck. Nólsoy resident Jens-Kjeld Jensen is reputed to be the finest taxidermist in the Faroes. He presents his stuffed stuff for visitors to buy and stuff in their packs. We were just passing by, so we didn't enter. Therefore, I cannot say for sure whether his workshop is stuffy or not.
During the summer, he also leads nighttime excursions to visit the Storm Petrel colony on the island. Check his website for details. Good stuff.
What to buy: Of course, you'll most likely want to buy stuffed stuff. Mr. Jensen also sells more touristy souvenirs, from postcards, to stuffed puffin head key chains (!), to refrigerator magnets. It's also likely quite enjoyable just to stroll through his workshop. However, note that entrance to the workshop costs Kr 30 per person. Should you buy some stuffed stuff, you'll most likely get a refund.
Nólsoy has a grocery store, where you can buy food and supplies for your walk. The store is small but the selection of items is good.