Nations, the 'modern' nation-states arose in the second millennium after the Resurrection in reaction to Pope Gregory VII's claim of total eschatological authority.
Eugen Rosenstoc-Huessy writes wonderfully about this in 'Out of Revolution'.
The word in Matthew is something such as 'ethne' in Greek, and is, it seems to me, obviously in contrast to Israel. Of course, in Revelation it's nations, tribes, people, and tongues, as people groups in different times in history.
Now, whatever civil magistrate authorities we have should vow to rule under Jesus Christ, who has all authority in heaven and earth, or else they are out of touch with reality.
And it's a timocracy--who has the riches, rules--and we in Christ are joint heirs with Him, and so we rule by prayers and actions, such that as we disobey God's wisdom in handling of money, God gives us civil rulers that do so also. http://www.biblicalhorizons.com/biblical-horizons/no-20-who-rules-the-land-the-meaning-of-the-noahic-covenant-part-2/
So, we rule already, and our calling is to make this more articulated.
Love in King Jesus,
PS: Economic corporations are the riches-accumulators now, and we are in transition. Search 'New Dark Ages Army War College' for a valuable paper on this. Also Creveld 'The Rise and Decline of the State'.