They would nuke Russia first. After that, Britain and after that the US.
Probably any allied city within range that wasn't already pounded to dirt.
And certainly also Moscow and Stalingrad etc.
Look up what happened to Coventry, over a kiloton worth of conventional bombs plus over 36,000 incendiary bombs. The damage caused was comparable to the nuclear weapons used against Japan, the only reason the death toll was significantly lower was because we had evacuated our cities and our warning system allowed almost everyone to get to shelters.
As a note they weren't the only ones who tried to wipe out a city, we dropped over four kilotons worth on Dresden (where the death toll was comparable to Nagasaki).
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It is, however it's worth noting that Stalin's kills per yer is less than 1/3 of Mao's (and half of Hitler's), and also that the figures for Mao and Stalin are a bit skewed as they get blamed for unpreventable deaths in their country as well as intentional.
Hitler: 17 mil over 11 years.
Stalin: 23 mil over 31 years.
Mao: 78 mil over 33 years.
Yup. In fact I think he killed more than Stalin and Hitler combined. I'll never understand why people think Communism is a good thing. Pseudo-intellectuals like to spout off these massive definitions of the differences between communism, fascism, socialism. At the most basic level they all have the same horrible thing in common: the individual means nothing. When 'the greater good' always trumps an individual you end up with really, really bad results....like millions dead. These 'isms' might appeal to some in theory, but human nature guarantees they will never work. It always ends the same.
Germany? London
Japan like the article suggests? America, probably Washington DC and New York.
Depends a lot on at what stage in the war they got the nukes. Realistically they would have gotten them when they were aleady heavily on the defensive, so most likely their first nukes would have been used on the advancing Russian armies out of pure necessity.