Here are some things to keep in mind:
1) TAKE EVERYTHING THE MEDIA SAYS WITH A LARGE DOSE OF SALT! That is pretty much recognized around here. You will never get anything but spin from either side. As much as I loathe to say it, social media right now is probably the only REAL news source in this whole situation and I even question it highly.
2) Putin is not an idiot. He has plans within plans. The western powers have shown weakness and devisiveness both internally and externally for decades. To him, this was the chance of a lifetime. In taking that chance he has painted himself in a corner. He is facing an insurgency that hasn't been seen in Europe since WWII and he knows it. He also realizes if he is defeated or humiliated, he loses face ergo power at home and can quite possibly wind up hanging around a garage in Moscow like Mussolini did in Milan in '45. This is what makes the situation highly dangerous.
3) If Putin goes all the way and orders nukes used, chances are they will be short ranged theatre weapons and not full scale ICBM's. He will do so in Ukraine first both to show the world just how far he will go to accomplish his goals and to take the fight out of Ukraine as we did the Japanese back in '45. Problem is that nukes are "highly problematic" for reasons all of us know. In addition, there will be some response which could quite easily turn Moscow into the 21st century version of Chernobyl. Putin already has an escape plan, count on it. The average Ivan doesn't. I don't know if the Russian people remember just HOW big a price they paid in WWII.
4) The involvement of NATO Forces in combat with Russian forces at this point is inevitable. It will most likely happen when Russian troops attempt to go into Poland or the Czech Republic after resistance fighters. This means ALL NATO members will either have to step up or capitulate to Moscow. Such a capitulation at this point in SOME western allaince countries would be met with "very unhappy populations" and lead down an even darker path. Others will simply shrug and go back to hunting Pokemon.
5) The UN has ALWAYS been little more than a joke not unlike the League of Nations after WWI. Except for resolutions and such, I see nothing close to what it did in Korea back in the 50's...this will be NATO vs. Russians and their allies all the way...that will include China, North Korea, and Iran. The fact that China hasn't gone into Taiwan yet is merely because they are waiting to see how the west will react. If they capitulate to Putin, Taiwan is doomed...and possibly so is Japan. I would pity them going into South Korea.
6) This has a great potential for WWIII. To think otherwise is not smart or prudent. History always repeats itself and this tired old story...with different actors, players, and times is no different. That is the sad part about this whole scenario...everyone loses. One of the reasons I brought up a lot of history in my entry here. I would hope calmer head prevail.