Himal Chuli is the sister restaurant to Chuatara and also happens to be the better one IMO. I don't know how traditional/authentic it is, but the food is light, tasty, and flavorful, and as a massive meat eater, I can say that they have some of the best vegetarian food I've ever eaten (most places are just too bland or funky).
Surprisingly enough, for a restaurant with such a strong vegetarian emphasis, they do have good meat dishes. My biggest issue with this place is the price -- they seriously could charge a little less... $9 for the amount of food served was hardly a bargain and $15 for the meat stuff? Ouch.
Atmosphere is cosy and quaint -- It's kinda quiet and bright and you get a nice view of State Street when you're sitting there.