Big companies do this all the time, so it doesn't really lower my opinion of Nissan at all. Go to Survivor.com and you'll see CBS has tried to get that domain as well.
Since they're spending millions upon millions of dollars on advertising to try and publicize the name Nissan, I can't really fault them for at least trying to get the domain. I'm not saying it's right, but you've gotta figure they're going to try.