New Jersey (NJ) and Pennsylvania (PA) have a reciprocal agreement. If the only income you earned was from a job in PA, then you are not required to file a PA return unless your employer withheld PA state tax. This would only be filed to obtain a refund.
File only your NJ resident return if this was your only source of PA income.
If you filed the PA return by mistake and included the wages, you should file and amended return, with zero income and attach a copy of your NJ resident return. PA will not tax you on those earnings. You can use a PA-40 Form and fill in the circle for "Amended Return".
