The concept of a "nuclear tsunami" has been discussed in popular media, fiction, and military speculation for decades. It refers to the idea that a nuclear explosion, particularly underwater, could generate a tsunami capable of devastating coastal regions over great distances. This paper examines the physics of tsunami generation, the effects of underwater nuclear detonations, historical nuclear tests, and scientific modeling studies. The analysis shows that while underwater nuclear explosions can produce localized waves and severe damage near the blast site, they are not capable of reliably generating large, ocean-wide tsunamis comparable to those caused by major earthquakes. Consequently, the notion of a "nuclear tsunami" is largely a misconception when considered in the context of transoceanic tsunami hazards.