If the bad guys use chem/bio weapons, then we should use tactical nukes in the field against their troops. Their arty will probably be sending the stuff over as they have no air force. Therefore, we respond in kind to destroy that weapon from attacking our troops. What better way to destroy bio than with nuke power? Use nukes? You bet your fanny we should use them. Not the big boys from a sub, but from our field arty.
I think a well placed MOAB would do the same job as a small tactical nuke.
Nice big fuel air fireball, mushroom cloud, and all the psychological "holy crap" effects it would have on the enemy, not to mention the lack of the nasty (literal) fallout from using a real nuke.
The Iraqi's wouldn't know the difference up front, but would have the same debilitating effect.