chinese wedding banquet
I had my banquet at Jade Palace in Flushing four years ago with 160 people. I really enjoyed it. There's also KB Garden across the way and East Buffet which also has private rooms.
In Manhattan, there's a gazillion in Chinatown but few north. There's Park Place/Pavilion (40-ish & Park), Shanghai Evergreen (obviously, shanghainese and not cantonese like the ones I've mentioned).
I've also heard there are quite a few Chinese caterers who'll do wedding banquets, too. That'll be pricey. Good luck & best wishes!!!
In Chinatown, all the big restaurants are equipped and accustomed to handling wedding banquets. I've attended banquets at Golden Unicorn, Triple Eight, and Nice. This past weekend, my cousin had his at Harmony Palace, but a lot of people were later complaining that the portions were on the small side. Outside of Chinatown, a friend had his banquet at Jimmy Sung's on E 44th. The decor is not as garish there and overall, the experience more sedate.
For that large a group, you would figure to need a large eating hall. Post to the Outer Boroughs board for Flushing suggestions, et al., but in Manhattan, Harmony Palace and Jing Fong are quite big enough. This subject has been discussed before, too, so you might check on some previous "Chinese banquet" threads.