Wouldn't be wiping out any cities, but it would still kill millions. Hiroshima still has a dangerous amount of radiation active in it.
You are underestimating how much damage a nuke will do. In a city like LA, most of the people will die if it is hit. Not to mention that the people who survive will most likely have birth-defective children.
Honestly I think that we should defuse and get rid of all our nukes. They aren't good for destroying militarily bases, they aren't used for bombing terrorist headquarters. They are used for killing innocent people. Especially the ones that the US has. I saw an estimate saying that if we were to nuke anywhere in the US with one of our own, up to 200M people would die. That's nearly 2/3 of the country. If we were to nuke a military base in China, it would also kill millions of other people. Also we have over 5,000 nukes. Why do we have so many? When would we ever need 5,000 nukes?