I just went to Nintendo World at 6:00pm and there was one person in line. Actually, he wasn't even there. His chair was holding his spot - apparently he went home to sleep and planned to be back at midnight. The weather in New York is really brutal right now and I honestly don't think there will be many people willing to stand in the strong wind and downpour rain overnight.
My plan is to head there around 4am when the rain is supposed to go from heavy rains and scattered thunderstorms to just showers. By 7am the rain will stop, so this is probably when most people will arrive.