Spiritually, a nuclear explosion would suggest a discharge of power, which, if not handled properly, could be destructive. Treated carelessly, that power can destroy ourselves as well as others.
Psychological / Emotional Perspective:
When we have suppressed certain parts of our personality rather than handling them, there may be some type of synergy (combined energy) that can become destructive. We would be alerted to this by dreaming of causing a nuclear explosion. The threat of such a huge explosion is enough to generate fear, sometimes unfounded.
Everyday Material Aspects:
A nuclear explosion is not always an act of war, but can sometimes be accidental. Such an accident can unintentionally have very far-reaching effects. To dream of a nuclear explosion can highlight our anxiety about great change in our lives. We do not yet know what effect that change may have. We do, however, know we must undertake radical change, but would prefer it to be a more gradual process.
Also consult the entries for Apocalypse, Atom Bomb and Bomb.