I looked him up, and I can't see why he'd be a DINO. He's one of the more conservative Democrats, sure, but unless he's actively attacking his own party as Zell Miller was, I can't see how he's a DINO.
I'd agree with that. Nelson is the kind of Democrat, who can actually win in "red"/conservative states - and if the Democrats are serious about regaining the Senate, then they are going to have to field candidates of a similar moderate ideological profile (and if it's needs to be a conservative moderate than so be it)
So, no he is not a DINO! He's a Nebraska Democrat. I don't expect liberals to be very strong on the ground there
Dave