I have a business based out of NJ (online and various festivals). We collect/pay out NJ sales tax. Will events in NY require NY sales tax ID too and collection of NY tax?

Yes, if you go to events in New York, you definitely want to register and pay the New York sales taxes.  Many events will not even accept vendors without verification of the sales tax.  See Sales and use tax and much prosperity!

Many thanks for the reply! Pretty much thought so but so appreciate the confirmation!

Kelly