If my boyfriend and I are in Las Vegas on vacation and he was hit by a drunk driver, do we find a lawyer here or back home?

You have to file in Las Vegas since the accident happened there, provided the drunk driver is a resident there and the NV court has jurisdiction over him.

I would recommend calling an attorney locally that you trust. They can then refer you to a reliable attorney in NV that can best represent you. If the drunk driver resides in NV then you would have to file there.  Always best to use an attorney you trust first and foremost.