Ukraine never had nuclear weapons. The internationally recognized successor state to the Soviet Union is Russia, any Soviet weapons in Ukraine belonged to Russia.
“The internationally recognized successor state to the Soviet Union is Russia...”
Well, one little problem with that is that the UN never actually held a vote to ratify that Russia is the recognized successor to the Soviet Union. The application was submitted but actually voting on it seems to have fallen through the cracks somewhere along the way. Certainly everyone has been behaving as if what you said is the case so it could be said to be “de facto” the truth, but perhaps not “de jure”.
Correct. But it was in Ukraine at the time. So the government in Kiev could have simply confiscated the nuclear weapons. But then the West would have sanctioned Ukraine. Maybe that's not a bad thing. They could threaten to nuke Moscow and St. Petersburg so the Russians will leave them alone. Eventually, the West will drop sanctions on Ukraine in 10-20 years. Ukraine is still able to sell wheat to the Middle East and Africa so they have some hard currency. The transition would be tough. But they can survive.