NATO does not expand (invade to grab land), it is based on voluntary membership application (although it is not truly volunteer since they are being forced, antagonized to join due to russia expansionism). New members are only accepted through vote. "NATO expansion" is well known as putin/FSB propaganda meant for a certain naive audience.
NATO borders with russia are the most peaceful with the low number of russian troops. Internally, Russia is not concerned about NATO, a defense alliance since Russia has the highest number of nukes.
In the media, they will use NATO expansion propaganda because there are naive clowns and useful idiots who will believe in NATO expansion propaganda. Do remember russia was fine with Ukriane joining NATO, they saw they can use it as propaganda to justify russia expansionism. http://www.en.kremlin.ru/events/president/transcripts/21598.
Ukraine public support for joining NATO was in the minority before the war, and only after invasion it became majority. Even after Ukraine said they won't apply to NATO, russia didn't not stop its expansion because russia expansion has nothing to do with NATO.
In fact due to russia aggressive expansion even more countries applied to join NATO. Putin knew that russia expansion will encourage more to submit application to join NATO. Putin was warned to stop russia expansion as that just cause more to apply for NATO membership, it is open to anyone. Furthermore note that expanding russia territories just bring russia closer to NATO, increasing russia border with NATO. Clearly it is not about NATO.
Even, without using NATO, putin will come up with a new reason like nazis, terrorists or LGBTQ or WMDs or security issues ( a country with the most nukes in the world has a security issue? only naive clowns will believe that) or restoring empire/imperialism (which he admitted in interview with carlson) or all of the above each for a different audience. Whatever it takes to get crimea and its warm water ports, and later Donbas for a land bridge and to secure Crimea water supply. Eventually going all the way to Transnistria.
You think things are so simple as poor top nuclear powered russia who is scared of evil tiny Ukraine, for suggesting sending in membership application form to NATO. You are being naive at best. War does not work like a superhero movie.
NATO was created to protect small countries from russia expansionism and stop russia from antagonizing its neighbours.
Russia was even member of G8 until russia antagonized G8 members by invasion of Crimea. The only way a massive nuclear powered russia sees NATO as a "threat" is that NATO prevents russia from expansionism... from expanding russia territories.
