The nuclear attack on Japan wasn't intended to defeat them - they were already essentially defeated, just trying to find a more favorable way to lose. The nuclear attack's purpose was to intimidate the USSR, as a power flex. The reason nuclear weapons are a deterrent isn't because a couple of nukes hitting your country is a problem - that's just a minor inconvenience when it comes to war. The reason nuclear weapons are a deterrent is because the countries that do have them have a lot of them, and can destroy not just a couple important cities, but cover your entire country in radioactive waste.

Not only will your "plan" not achieve its goal, but it will also hurt hundreds of thousands, possibly millions of civilians. I know it's popular to associate a people with a government, and that's not completely baseless, but - and I can't believe I have to say this - that's absolutely no reason to launch a nuclear attack. That's just genocidal nonsense. There's a reason countries at war don't kill civilians, and it's not "good will".