The deadline to grieve your property tax assessment in Nassau County is less than two weeks away. If you live in an incorporated village, it will now be easier to appeal a denied claim. A State Supreme Court ruling says Nassau homeowners should be allowed to provide their own evidence to argue unequal assessment and have their assessment reduced. Previously, a Nassau County Supreme Court judge ruled that evidence provided by homeowners for an unequal assessment argument would be inadmissible. But now, the appellate court judge says those homeowners were wrongfully denied. The ruling could reopen thousands of claims. The deadline to file a property tax grievance in Nassau County is March 31. In Suffolk, the deadline is May 19.