Near as I can figure, the nukes from SS3 are more of the directed energy type warheads, effectively a HEAT round writ very large since they do not require a direct impact.
Or the non-nuke warheads were more the 'SAM' variety counting on a buckshot pattern cloud impacting at speed- or perhaps that is the 'impact' type as opposed to standoff detonation.
The smaller cheaper nuke warheads come in at 10 hits per warhead, the more expensive ones can go to 100 hits, which for an ACS CT ship makes 'not vaporized' rather academic.
Presumably the bay missiles could have even larger more expensive and destructive nukes.
Detlasers certainly feel better from a probability of hit perspective given a nuclear detonation should drive many laser shots.
When considering varying missile rules/options, don't forget those awesome SS3 impact speed rules, a normal warhead missile can do near light nuke damage just hitting from a zero speed start, and say a fighter imparting some high vee could be giving Ye Olde Homing Missile a cruiser crippling punch.
Nukes and high vee impact together is Just Ugly, I presume that's the velocity of the nuclear fireball with a little oomph/direction from the missile's vee.