Nuclear Weapons in Interstellar Operations
There are some detailed rules for making nuclear weapons in Interstellar Operations, and according to the rules, the smallest possible nuke has an 0.01 kiloton yield, a mass of 5 kilograms, and can be deployed as an Anti-Mech mine. It also destroys everything within 450 meters (not including the heat, electromagnetic pulse and ionizing radiation that spreads out a lot further), fitting for what's basically a Mini-Nuke.
Note that the warhead itself doesn't weigh 5 kilograms (just slightly heavier than an LRM) because of the payload, that's just the minimum allowable mass for nuclear weapons under existing BattleTech rules, and it does not include the mass of any launching mechanisms or guidance systems. ~Amaroq Starwind~ (talk) 15:24, 29 March 2018 (EDT)