Yes, you can have 529 plans in multiple states.
If you work in New York and pay New York State income taxes, you may be entitled to a state tax deduction of up to $5,000 ($10,000 if you're married filing jointly) on contributions to your 529 Direct Plan account.
For more information, check NY 529 College Savings Program
For NJ , you can deduct up to $10,000 of contributions made during the year into an NJBEST account.
NJ Division of Taxation