Well, they don't have NCO Corps, may not even have TOC.
There are virtually no chances to launch a nuclear attack.
It will not do enough damage to Ukrainian for them to stop, you may destory a city or 2, that will only make the civilian population suffer, not the military force, and the Russian objective is land grab, what good does it do to nuke the city they want to take? And finally, it may most likely provoke the west to attack, when you stack all these reasons together, you will see the chance of nuclear strike is almost zero.
Well, they died for toilet seat, sink, and TV. That's good enough.
I mean, what do you think they are expecting back home??