You vehicle is considered "New" as long as it is under the Nissan Factory 36 Month / 36,000 Mile warranty period.
New Vehicle plans are effective on the date the vehicle was first sold new and the mileage starts at Zero. For example: If your vehicle is 14 months of with 15,000 miles and you purchase a 60 Month / 100,000 Mile New Vehicle Plan the vehicle will be covered for 46 additional months or up to 100,000 miles, whichever occurs first.
The "Pre-Owned" plans are the same type of coverage, the difference is in how the time and mileage are calculated. When you purchase a Pre-Owned plan the time and mileage start on the date you purchase it. For example: Your vehicle has 37,000 miles and you purchase a 60 Month / 60,000 Mile plan; the vehicle will be covered for five years from todays date or up to 97,000 miles, whichever occurs first.