>Because to me a bunch of people running around changing
>allegiances based upon the rise and falls of numbers they have
>no control over and who go out of their way to target good
>purely for good sakes seems both chaotic and evil to me.
>
>If it's not? How is it not?

Sure:

1) If we're going by the old school Gary Gygax original definitions of the alignments, True Neutral has to be exactly what Nexus is. Now, I always kind of found that formulation odd because while I think "I religiously try to balance the world" is a way to play Neutral/Neutral I don't see it as the only way -- by the "originalist intent strict constructionist" esque view of alignments, Nexus is certainly that and not Chaotic Evil.

But let me throw that aside for a minute and explain it a few other ways.

2) Always changing your allegiance to benefit by being on the side with the greatest numbers is very arguably Chaotic Evil. The problem is, that's doubly not what Nexus does. First, because they're always switching to the underdog side, the disadvantaged side (indeed, they can get a kick in the ass for killing the 'weak' side, even if they didn't start it!). Second, they're not switching for their benefit at all -- they're switching (possibly -- different Nexus can have different motivations, but let's deal in archetypes) because they see it as the right/proper/appropriate thing to do.

3) Or, look at it this way: is a Tribunal chaotic evil because they attack a criminal? I mean, that guy wasn't wanted five minutes ago. They probably don't even know why he's wanted. Their cabal rules say, now this guy has to die when he didn't before, and they kill him.