Ah, you mean the Shipwreck and Depth Charge (WE-177). The latter is one I often forget about, and is actually very cool. The Shipwreck, which is also in AT (albeit non-nuclear), is not much different than the standard payload short of detonating further away from the target while still destroying it.
When you originally asked about nukes, you phrased it as if you wanted more than low yield tactical ones (so do I), so I wasn't even thing of these.
