|The following is based on Fallout Tactics and some details might contradict canon.|
A Nuke carrier is drivable vehicle in Fallout Tactics: Brotherhood of Steel.
The nuke carrier is fundamentally the same vehicle as the Armored personnel carrier, but instead of hauling an armored passenger / cargo compartment, it's hauling a live, nuclear warhead. The Warrior uses it to carry a nuke to the door of Vault 0 to blow it open, so the final battle against the Calculator can begin.
Nuke carrier appears only in Fallout Tactics.