If the wheels were supplied new with the car and are less than 3 years old I would visit a Nissan dealer and see if they will support a warranty claim or at least a goodwill gesture - which can sometimes be secured, and even if they a little more than 3 years old. Surprised you did not query the condition though at the time of your purchase?
And yes, if they were bought as 'aftermarket' wheels than the 3-year protection would not apply. First thing is to establish if they were supplied with the car from new - check with the supplying dealer.
But having said all that, Nissan might say it is the way they have been cleaned, albeit not in your ownership and noting you have not used the metal polish shown in the pic, or other abrasive cleaner to further affect the lacquer.
Given a set of Nismo wheels currently command s/h prices well over a grand, even if not in perfect condition, it is certainly worthwhile getting something done, particularly as they are such a great looking wheel.