The last time two nuclear powers (India and Pakistan) had a war it almost killed us all and they only had atomic weapons. The Ukraine and Russia both also have thermonuclear warheads (aka “H-Bombs”).
I don’t think Ukraine still does. Past tense only.
Upon the breakup of the Soviet Union, Ukraine inherited the third largest nuclear weapons stockpile in the world after the Russian Federation and the United States. However, in the January 1994 Trilateral Statement, Ukraine committed to full disarmament. Kiev joined the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) as a non-nuclear weapon state in 1994, acceded to the Strategic Arms Reduction Treaty (START I), and having transferred all of its nuclear warheads to Russia for elimination, became nuclear-weapon-free in 1996.
http://www.nti.org/country-profiles/ukraine/nuclear/
The Russian-loving former wannabe dictator of Ukraine gave those up over a decade ago along with some bombers that weren’t scrapped. The pro-Russian regime looted the country and military and now that it was overthrown, Putin invades
Ukraine has no nuclear weapons. They gave them up with the promise that the US and Russia would assure Ukraine’s security.