The Cold War and nuclear weapons helped one another to develop. That is, the existence of nuclear weapons helped to bring the Cold War about and the existence of the Cold War helped cause nuclear weapons to become more developed.
Without nuclear weapons, it is very possible that the Cold War might not have developed as it did. Instead, it might well have turned into a “hot” war. If there had not been nuclear weapons, either the Soviet Union or the US might have been willing to go to war with the other. Perhaps, for example, war would have broken out over the issue of Berlin. Because nuclear weapons existed, neither side was willing to go to war.
Without the Cold War, nuclear weapons would, most likely, not have become as developed as they did. Because of the Cold War, the US and the USSR both felt that they needed to get ahead of the other. They both felt it was a matter of national security. For this reason, they developed more and “better” nuclear weapons. They developed hydrogen bombs and ICBMs as a way to deliver those bombs. They developed stealthy submarines from which missiles could be launched. It is unlikely that they would have gone to all of this effort had it not been for the Cold War.
Therefore, the Cold War and nuclear weapons helped one another to develop.