You learn a bit about history in the region you'll know that Russia has been being the aggressor for about 300 years, but has always felt the victim. Stalin in the 1920s even had the phrase "capitalism encirclement", not unlike Putin's "NATO encroachment". This is despite the fact that it was Stalin's strategy to chase trade agreements with the UK, Germany and France, while at the same time supporting the respective countries communist parties attempts at revolution. As you see, the pattern of behavior has changed since then.
So no, NATO isn't the aggressor.