You will need to report it on both your North Carolina return AND on a New York Non-Resident return. North Carolina will give you a credit for tax you have to pay to New York, so you won't be double taxed on the gain.
For the basis of the property, since it was a rental for 30 years, the building would have a cost basis of zero, so the remaining cost basis would be the cost of the land. And although the cost basis is zero, you will have to deal with depreciation recapture. So you will need to determine what the original cost basis was, because that is your depreciation. (Note: The gain and depreciation recapture is calculated based on depreciation that could have been taken, not the actual depreciation taken.)
Finally, if you have not been filing and reporting rental income and expenses on a New York non-resident tax return since you left New York, you might want to consider contacting the New York Department of Taxation and Finance to discuss how to proceed.
