Click somewhere on the map and a nuclear missile will hit it and detonate.
You can set the size of the shockwave in the Nuclear Strike options.
(if u set it to 0 the shockwave only effects the dynamic parts of the map. like: Vehicles, AI enemies, ragdolls, props, and dynamic creations.)
You can also aim and fire nuclear missiles from a B-29 Superfortress bomber that flies over the map.
Oil Ridge, Micro Metropolis, Colossus Attack, Muratori Beach