Oh yes NATO expansion definitely occurred; Poland, Slovakia, the Czech R. and a host of other countries joined NATO in 2004 as well, all of which were formerly Warsaw Pact countries.

The thing is these countries joined voluntarily. A second point is that NATO never said they would not expand.

When it comes to Ukraine, Moldova, etc., NATO expansion was not on the table because of the institutional problems within those countries. And that's where Putin's argument falls short.