Ukraine was a nuclear power in the same way Japan, Germany, or Turkey are now. No control over the actual nukes, just being protected by them as deterrence, but

Ukraine was a nuclear power in the same way Japan, Germany, or Turkey are now. No control over the actual nukes, just being protected by them as deterrence, but also thereby becoming a target in case of a hot conflict. Oh, and also the capability to develop the capability on their own, since they have lots of nuclear reactors and nuclear scientists.