If your permanent legal residence - your "domicile" - is in New Jersey, you are an NJ resident and all your income - wherever earned - is taxable by New Jersey. The money you earned while physically working in South Carolina is taxable by SC. NC considers you a non-resident for tax purposes "if you are a legal resident of another state" (http://www.dornc.com/taxes/individual/resident.html). If you earned no income from physical work (or rental property) in NC, and you are an NC non-resident, you need not file an NC tax return. Therefore - if I'm understanding your situation correctly - you should file (in this order):
1. federal tax return
2. non-resident South Carolina tax return
3. resident New Jersey tax return.
On your NJ return, you'll be able to take a credit for tax paid to SC on the same income.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
