I think the horde is equal to the Alliance on how lawful they are.
I mean, the Orcs are faaaaaar more lawful than Humans. The only reason Orcs gave into bloodshed was because they were under demon control. The Tauren are arguably the most peaceful race in the game. Trolls are territorial, so they are kind of chaotic. The undead WERE chaotic, but now they just want to get on with their lives peacefully. Blood elves are the evil ones all together I think. A lust for power and wealth is evil apparently.
Humans are racist, war hungry, dangerous, meddling, parasites. Night elves just constantly blow the world up. Dwarves are obsessed with Conquest. The only truly 'good' races are the gnomes and draeni (or however you spell it.)
Goblins are painfull neutral, but leaning toward chaotic. Worgen, again, leaning more toward the side of evil than the goblins.
So I'd be horde. The lesser evil.