This time it's all of NATO plus Ukraine and Georgia against Putin's Russia. Byelorussia remains neutral. So does China.
A win is getting to Moscow and deposing Putin.
No nukes.
Could NATO succeed where Bonaparte and Hitler failed? There's less space to conquer without Ukraine and Byelorussia and the Baltics. But of course Hitler captured all of them fairly quickly and then got bogged down. But Hitler's problem was manpower vs space to conquer. He had to control Ukraine. He pissed off the locals as well and they kept quite a few divisions tied up. Plus he was distracted by his Antisemetic policies which tied up huge numbers of troops. But still I just watched a special on Operation Bagration. What a horror show for the Germans. Even if it could be done it would be rough.
SLD
I don't think NATO plus would have any problem at all winning such a war, on a purely military basis. The only way they could reasonably lose (given that nukes are off the table) would be due to political interference with military command and control decisions.
But there's the rub - Winning the war is unimportant. Winning the peace would be essentially impossible. The US (plus a handful of allies) thrashed the fuck out of Iraq militarily; It was no contest at all. Russia would put up more resistance, but frankly, couldn't put up much more - even without the rest of NATO plus Ukraine and Georgia providing anything other than free access across their territory for US forces, the US alone would kick Russia's arse - The things that prevented Bonaparte and Hitler from doing so are not serious constraints for the modern US army. Logistics is everything; The US military has vast logistic capabilities, and could expect to establish air supremacy in short order. Without effective enemy air attacks on logistic convoys and cargo aircraft, it would all be over in weeks.
So, like in Iraq, you now have 'control' of a large nation with no effective government,
populated by a variety of people with ancient grudges against each other, whose only shared belief is that the American occupying forces are the enemy. We know from Vietnam and from Iraq that a vast asymmetry of force is of massive help in defeating a conventional 'nation state' enemy, and that it is equally useless in defeating guerrilla tactics by small groups of poorly armed but fanatical citizens of an occupied nation.
The Russians won't just give up and stop fighting once Putin is deposed. You would be looking at many decades of high US casualties, in a vast nation where the new US (or US puppet) regime controls only the major cities and highways (and those only during the daytime). And all of this would be for what?
Sure, you could win, and win easily. But the consequences of that victory would all be bad, for everyone involved. So it would be a stupid thing to do. Even after nukes have somehow magically been taken out of the equation.
The idea that a big army can go and take over a country, and that the losing side would just go away and leave the spoils to the victors has not really been accurate for a couple of centuries. The defeat of the Axis powers in WWII was the exception, not the rule; Fascists were nothing if not obedient to authority, but even so the Marshall Plan, with its massive spending on reconstruction, and a significant and expensive 'de-nazification' program was required. Compare the response of the occupied European resistance movements acting against the Nazi invaders - non-fascists simply didn't lie down and accept their fate.
Maybe, just maybe, in the Stalin era, an invasion of Russia by anti-Stalinists might have worked (assuming that the invaders were kind and generous to the people they liberated). Certainly Hitler would have been well advised to treat the anti-Stalinist Ukrainians better than he did, as they could have been far more effective that they actually turned out to be. But today's Russia isn't a totalitarian Stalinist state. It has it's problems; But things are better than they have been in forever - and about as good as you can expect given the conditions under both the Tsars and the Communists. Today's Russians (mostly) wouldn't welcome NATO or US forces as liberators; They would (mostly) despise them as foreign invaders of the motherland.