[Dallara]

The Tribeca Grand is probably the nicest hotel that's an easy walk from Nobu. It's only about six blocks or so. The hotel has a pretty nice bar (by nice, I mean it's a fancy lounge with plenty of beautiful people and expensive drinks). The only negative is that the rooms are a little small, but most hotels in NY have that problem.

Edited to add that Le Pan Quotidien is a good recommendation for lunch around the park.