This is something that's been on my mind for awhile. I read a story, in which a Standard Template Construct system that produces Iron Men is found. The planet it was found on, however, has been under the influence of Chaos for some time, and when the STC is switched on, it immediately spits out a decidedly demonic Iron Man.
This got me thinking of the Necrons. Now, as I understand it, the entire Necron race was created before any of the chaos gods had arisen, so they couldn't have been built with explicit defenses against taint - they wouldn't have known about it. Added to this, the fluff regarding the C'tan and the Necrontyr indicates they simply cannot fathom the warp.
So, the question I have is, could a Necron be tainted? What would happen if one of the worlds sucked into the Eye of Terror were a Tomb World? Could you have an army of Chaos Necrons, lead by a Nightbringer style greater deamon emerge?