The timing of these rumors leads me to believe that Nader thinks he'll get a bunch of support from the Deaniacs now that their horse has dropped out of the race.
The thing with Nader is that he has a genuine disdain for both political parties so when people appeal to him by saying if he runs it helps Bush win the election, he doesn't buy it. He won't acknowledge that publicly, at least. The problem he has is there just aren't enough uber-liberals out there to actually get a far-left candidate into office. There are more variations of conservativism that a third party candidate could perhaps run on which is why Perot managed to get as many votes as he did.