Yes. Nintendo sued someone who handed out flyers with Pokemon on them. I have a strong feeling about this one.

the pokemon company has sued over much, much less.

Of course. WBC is creating derivative works using designs that are copyrighted. That unauthorized use would be copyright infringement.

I chose you Copyright laws!

If WBC keeps using Pokemon in their promotional material, would Nintendo have precedent to sue them for unauthorized use of their IP? Because that is a battle that I would love to watch go down.