Well, I cannot imagine wizard dieing to a nuke. You would have to surprise them I suppose. I mean, what if they teleport the nuke to some other place?
Even if all the tech kept working, I imagine the only way you could beat a wizard as a Muggle is if they don't see it coming.
If they see a gun, sure, the first wizard may be surprised and die, but it will not take long to find a spell that shields them. Rockets? Same story. Sure you can destroy stuff, even kill a bunch. The rest will be back though, and they can teleport, change memories, actually turn into another person or animal, turn you into an animal and whatever else.
The one plot hole in HP that always annoyed me is how Avada Kedavra is supposed to be the worst spell. In the books it is mentioned how Peter Pippeling blew up a whole street with a bunch of muggles in it. That seems way more dangerous...