I'm not a lawyer but I stayed at a Holidan Inn last night (actually, I didn't even stay at a Holiday Inn!).

Probably, leagally, if Nissan wanted to, they could stop you from using the logo if they found out and felt like ordering a "cease and disest." But realistically, nobody high enough up the ladder would find out and if they did, probably wouldn't care because you're small peanuts and not making a profit off the logo. You're not even on the radar. And worst case cenario, somebody finds out, they tell you to take off the logos, and you take them off. It's a non-issue.

Faghetabahtit.