Ukraine was a successor state to the Soviet Union. They retained control of those nukes on their territory just as Russia did for those on their territory (Russia is not the old Soviet Union, as so many here like to remind us). They gave them up in return for guarantees that Russia would respect its borders. We can see how well that work out.
Ukraine in 1994 was still Russia. It took a few more years for Nationalist NAZI ilk backed by the west to fan the flames of ethenic hatred in Ukraine as they were actively doing in the former Yugoslavia. Race and Gender are the favorite tools of the FDR Democrats today.