How can i report a nightclub for discrimination? This is a NYC nightclub?

Welcome to NYC. They're allowed to deny entry to anyone they want, and unless you can prove it was because of your ethnicity or gender you're going to have a hard time doing anything about it. The reason was probably the way you were dressed, or maybe the bouncer didn't like the way you acted or whatever. Part of his job is to weed people who are underdressed or too bridge and tunnel, because that makes it an exclusive club. Exclusivity means they can charge more and get away with having a 45 minute wait to get inside. If you really have a problem with it, don't give them your money. Go somewhere that will let anyone in no matter what.