Answer:
Theoretically, Yes, but there are many details involved in this and it is so very unlikely to happen.
Explanation:
A Nation can take over another nation in order to free its people from a tyrannic ruler, for example. As long as, eventually, those people become part of a democracy-like system in which they can be well represented, have no rights removed, and are granted freedom, you might say that they were not oppressed, but freed.
Unfortunately, history doesn't often has examples of such a happening, since when a nation takes over another, it because a ruler seeks dominance and the increase of his or her own power.
