What if the US created a time machine and sent a nuke to destroy ancient greece in 776 BC?

A nuke burns a city to the ground. Maybe even burns the fields around it. But it doesn't change the course of rivers, doesn't change the trade winds, doesn't change the layout of the roads.

Why would "Greece" be destroyed by "a nuke"? Cities burned down all the time in that age. People would rebuild them. Fields might dry up, crops would whither, entire regions die from hunger and disease. But survivors would replant the fields, rebuild the houses, have a bunch of babies and have land enough for all of them. That's how agricultural civilizations rebound from disasters. Disasters don't end them.

A nuclear explosion is a terrifying event and for a modern person it's a horror scenario because of what we know about them and about the kind of war that would see them used. To a person from ancient Greece, a nuclear explosion would also be terrifying as hell but he'd have ways to rationalize them in ways that don't leave him traumatized. People in that age told each other stories about powerful and arbitrary gods who would do with mortals whatever they wanted. They'd say "Zeus punished the city and that's why it went up in terrifying flame and smoke" and when they tell others that story it becomes a relatable event. It really wouldn't end their civilization.