The mass necessary to fuel the transport a nuclear weapon across light years of space is so large that there would have to be some reason to do such a thing in the first place. I mean, if you can move something that far, you don’t need to use a nuclear weapon, just move a rock a little bit so that it hits us. That’s much more logical. And these things tactics don’t make sense either. THere isn’t any reason to use nuclear weapons. Planets like ours appear to be pretty scarce, so they’re valuable. You wouldn’t want to damage it.
I can’t imagine wanting to trade with aliens. I think it’s more likely that we would be pets. You don’t nuke pets. You catch and breed them.