Verican: I think an argument could be made that they could look at themselves as the good guys. They are a united nation, who if able to conquer the north would bring relative peace across the land, and get rid of racist policies and ghettos where the elder races are piled together. Seems to be the way Nilfgaard operated from what I have read in this post, I am looking forward to seeing how they are in the novels.
They're not for anything like equality or peaceful coexistence among the races. They're not hell-bent on exterminating pointy-eared or stumpy bearded folk the way many Nordlings are. But neither are they above establishing puppet states like Dol Blathanna, with the purpose of using these to sow enmity between the Nordlings and the nonhumans.
It's as if the British were to make treaties with the Native Americans then induce them to wage war against the Colonials. Oh wait, they did that.