A "nuke" is simply slang for "nuclear weapon", and the US deployed two in WW2. It sounds like you might be talking about fusion weapons, which have certainly been tested but never used in anger; these are, in effect, just bigger bombs. No one bomb that humans possess can wipe out the species, or even make a dent. Nor is it a given that a single nuclear attack will lead to nuclear war.

As to why no one's used nuclear weapons since WW2, it turns out they're not hugely useful weapons outside of a "total war" context. Too blunt an instrument; rarely do you wish to simply wipe out a few square miles and everything in it.

I predict the first use, if it happens, will be naval.

Omg. What i learned would not allow the comparison and analysis you used.

I wish it was 1979 again and i could have recorded my physics prof...

If you can't remember the evidence how can you be so certain?

Doesn't the fact that hundreds of nuclear bombs have been tested without destroying the species hold any weight?

Perhaps the argument is the retaliation would be world ending but even that is not clear.