I have been thinking about this as well, and honestly I would make it a relative scale. If both sides are using similar technology levels, the rules work fine. Ordinary riflemen = d6, veteran commandos = d8, etc.
Bombs/Artillery I would treat as a miracle attacking all tokens in the area with whatever strength you feel is appropriate, but I would keep it low. Historically bombs were more useful for taking out emplacements and infrastructure than wiping out tokens and artillery was never very accurate... more for morale destruction and the occasional kill.
A nuke, well... do you really need rules? A nuclear blast will wipe out ANYTHING mundane at ground zero, and by the game's rules nothing can penetrate a god's aegis unless it is supernatural in origin. So someone nukes your god, he'd be standing there annoyed with a radioactive wasteland around him no? I guess you could start it off at a d100 at ground zero and scale back as you get further out from the main blast. Not sure how you'd do radiation sickness.
For mechanized forces such as tanks, I would follow DarkServant's advice and have them count as more than 1 person in the battle.