Nan is asian/french cuisine - and probably one of the best meals we had this week.
The sauces were excellent. Supremely tasty, light cream sauce under my bass, something with ginger and basil under the crab cakes that I wanted to lick off the plate! Sauces with the meat dishes seemed to be made with stock reductions of pan drippings - but they weren't greasy or heavy. The duck was crispy and tender, not dry and not at all fatty.
The space is clean and light-colored. The wait staff is pretty involved in the restaurant, our waitress makes the ice cream (they do it all on premises, and the pear sorbet was perfection).
It's BYO, but they do a good job opening and taking care of the wine.
We went on a Thursday at 8 and pretty much closed the place down :) When we got there it was about half full, there was a big group doing a wine tasting, some student-looking folks, and a few other 2 and 4-tops.
4000 Chestnut St , (215) 382-0818