The nationalism in Ukraine is crap, but fucking understandable given that the area have been dominated (and starved) by other powers, Russians, Poles and Lithuanians for centuries. The Fascist elements are alive and kicking because they were the last group to resist Russian dominance. I mean.. Rotten ideology, but understandable in the case of Ukraine.
Now as of the motives of Putin. They are primarily at home. To boost the humiliated spirits and ego of the Russian people, and probably to secure his own re-election.
(It's not like Russia need more land, and that Russians in Ukraine were threatened in any way is pure BS. People in Eastern Europe rarely have a problem with Russians, they have a problem with Russia.)
I do understand some Russians in here feel a bit of bold pride over seeing their president outmaneuver the rest of the world, but I'm deeply worried this move will not pay off for Russia. It will isolate your country even more, force countries away from using the gas both sides depend on. With crashing gas prices, Russia would have to produce other export products to compete in the rest of the world. Funnily, the only Russian export besides (gas/oil) aging weapon technology I can think of is Matroshka dolls.
I'm pretty sure Putin will even grab more of Ukraine, and then I'm deeply worried he will actually have signed a kind of death penalty for Russia. If not death, then a long long prison sentence. You will experience more poverty, and in the long run a weaker state. When the time comes the west will be ready to consume the vast resources you sit on. And like Russia waited for Ukraine to be weak, and perhaps even engineered the weakness, the rest of the world will wait until Russia is weak.
I think Russia is facing more poverty, more propaganda, more extrememism, and a more totalitarian state in the future. Sorry.