Don't know if it qualifies as "nice" but I suggest you contact NYU and other local universities, since they are known to offer student housing during the summer. Given the difficulty of finding short term housing in NYC, you would need to get on their lists right away since these fill up very fast.

And congratulations for landing a summer Wall Street position!

What kind of location do you want (and what qualifies as "nice" for you?).

If proximity to Wall Street is important:

- NYU and The New School both have dorms downtown; The New School has one right on Williams Street about 4 blocks from Wall Street. But I don't know that you'd want to stay there necessarily!

- There also have been a lot of "luxury" residential units created down there in the last few years, which may possibly have reduced rates due to the economic downturn...

- Also look into sublets in Battery Park City. While a little removed from the center of things, BPC is an easy walk to Wall Street, and pretty gorgeous in the summer with their parks, the marina, etc.

If nightlife, walking distance to non-work activities, or variety/quality of eating options are more important than proximity to work, you'll probably want to choose a different neighborhood.