I referenced Chechnya because it is a very traditional case of colonialism that very obviously parallels other European colonies in Africa etc: acquired through straightforward territorial conquest in 18-19th century with no justification other than "might is right" (with a dash of "white man's burden" thrown in for good measure), specifically to exploit as a colony.

Ukraine is a bit different in that both the official Russian ideology and the prevailing public opinion don't see it as a colony, but rather as "lost heartland" that is inhabited by what are still fundamentally Russians who have "strayed". So the long-term goal there isn't to acquire a new colony for the metropole to exploit - it's to forcibly assimilate its Ukrainian population into the metropole in its entirety. Now in practice this isn't that simple either, because of course the occupied territories are exploited. However, one could argue that it is still not colonial exploitation, because its economic nature is fundamentally the same as the relationship between Moscow and basically every other Russian region. That is, it would make sense to say that occupied Ukraine is a colony if you're also willing to say that pretty much all of Russia is also effectively a colony of Moscow (which is not an unreasonable way to describe it, to be fair - just not a conventional one in Western historiography).