The nuke is overkill, just think of the collateral damage. I was thinking more in line with a long distance surgical weapon, like at .50 BMG, or a .338 Lapua.
Is ammo available for the 23mm A/T?
We had a collection of 25mm spent casings and would reload using pulled rounds from the 25mm Bushmaster Chain gun on the Bradley. Only down side was the $ 200 Dest/Dev tax per round. That was why we sleeved it for a 50cal. Much cheaper to shoot, but not quite as much fun.