If Box 17 is blank on the NJ state copy, that means that no NJ taxes were withheld from your pay. If you lived in and worked in NY all of 2017, you need only file an NY state return.
The only exception might be if you were a telecommuter for an NJ employer, working by computer from your NY home. Under certain circumstances NJ taxes non-resident telecommuters.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
