Wakanda vs DC USA
Relations break down between Wakanda and the DC United States of America. The result is WAR.
The scenarios are:
1) DC USA forces invade Wakanda
2) Wakandan forces invade DC USA
3) Battle it out over neutral ground
Each side gets standard government & military forces and tech as depicted in their respective universes.
For superhumans/metahumans, each country can only call on those characters who are shown as regularly in service or hire of the governments and military eg. DC USA gets guys like Wraith and Suicide Squad, but they can't call up guys like Superman, Batman etc.
Version is up to you... Preboot, DCnu, President Luthor era USA etc.
Who wins???