A rough analogy would be this, if the United States broke apart South Dakota would have hundreds of nuclear warheads but the South Dakotan Governor / State National Guard would not be able to use them because they never had the ability in the first place.

It is not at all clear that it was a stupid idea.

The nukes were useless because Russia had all of the access codes and the ICBMS had a minimum range of 5000 km. They could hit the USA but couldn't be aimed at Russia. The rest were disabled and Ukraine didn't have a nuclear weapons program or ability to repair them.

If they tried to keep them, they could have faced retaliation or attack from Russia, the United States, and other NATO allies.

US and other Western troops (not NATO per se, though I think all were NATO members) were openly present in Ukraine training the Ukraine military up until shortly before the recent Russian escalation of their long-running invasion of Ukraine (they were pulled out to avoid getting caught up in direct combat with Russia in the event of an invasion.)

EDIT: if you need a source, here's an article on the US/UK trainers being withdrawn: https://www.forbes.com/sites/annakaplan/2022/02/12/us-uk-pul...