OK, some thoughts from the Dagliash chapter and about the Nuke. I for one feel that Kellhus knew nothing of the Nuke. Also, he knew that Dagliash would be where the Consult would hatch a trap and it would be the most likely spot for their first confrontation.
They will come,” Kellhus had warned. “They will not abandon such might as the Horde manifests to our design . The Unholy Consult will intervene. At long last, my brothers, you will vie with our foe in the flesh, grapple with the Cause that moves you."
As others have pointed out, Kellhus was amazed and confused he he can be when he first encountered the Nuke. Having the Ordeal flee is a clear sign that he didn't want to sacrifice them and that he was very surprised about the Nuke. Now, I've seen where people say that sacrificing Saubon is proof he knew of it. But, Saubon was going to be sacrificed regardless. When Kellhus would've been finished making new ground of Virus and elemenating the Bashrag, he would have left the same as he did withe Nuke. And, I am a firm believer that Aurang was there to activate the Nuke, rather than just be a spectator.
One tomb plundered to fashion another. Shivers through oceanic stone. The slip of fractures as old as old. The spit of dust from the ceilings. Some halls collapsed, be they humble or majestic, rooves clapping down, pounding wails and velvet dust through all the forking, subterranean hollows. And the beasts beat their cheeks for the stinging of slovenly eyes. The mulish barks of the dying set them baying in their thousands, strung and clotted through the veined deep. Anguish and outrage popping through sputum. The bellowing of elephantine lungs. Where were the Old Fathers?
From the perspective of the Sranc/Bashrag in the well of Viri, clearly waiting on Aurang to show up as part of the plan.