Well, maybe not that big. Per this app.... https://nuclearsecrecy.com/nukemap/ .... China’s mainstay ICBM warhead (5 megatons) would only destroy from Perth Amboy to White Plains.
While Long Island would not be destroyed by a nuke hitting NYC, prevailing west to east winds would cause serious radiation poisoning for most residents of the island—and the entire island (many millions) would have to be evacuated if it was feasible to do so.