Nirvana is a solid lunch option for the working stiffs uptown. I eat here 2-3 times a month and it helps get me through the morning grind when I know I'm heading here for lunch. It's pretty much a "to-go" type of establishment, but they do have a few tables out front. I usually try to eat this stuff outside as the aroma is way too strong for the office. I don't want to make my co-workers too jealous!
I usually stick to the vegetarian options (it's cheaper and you can get a lot more food for the price), but everything I've had has been delicious. Indian food just has that 'POP', and Nirvana delivers it at a good value. Yes, the naan is just pita bread as others have mentioned, but it's still good. Make sure you also know your limit when it comes to spicy food because they usually have 1-2 entrees that deliver a big kick. They'll let you know if you ask.
Bottom line, it's a tasty, cheap, and quick lunch Uptown. I just have to watch it because sometimes I want to curl up under my desk and take a nap after chowing down!