Go to http://www.nissan.com and you'll see something about it.

If he was using this to:
a. Mislead people looking for the car company and sell them stuff or whatever
or
b. Use his site to promote auto-related services
or
c. Simply using this to "blackmail" Nissan Motor Corp. into getting a big fee for the name rights

... then the US courts probably would block him. Otherwise he'd win and Nissan might offer him big money for the name rights ... it's happened both ways many times before.