Really, it's going to look wrong no matter what. Here's the grammatically correct version, unless I'm somehow wrong:
No Nation may be ejected or banned from the region, or banned from any forum; nor may they be granted the power to eject or ban from The North Pacific; nor may they use that power unless expressly authorized pursuant to the Constitution or the Legal Code. Any ejected or banned nation shall have prompt recourse to judicial review of the matter.
Semicolons can delineate lists if list items themselves contain commas. The "unless" phrase isn't a clause, so it shouldn't have a comma.
It still looks unclear to me, though, since the "unless" part looks like it only applies to the last item in the list. I tried moving it around, but I couldn't make it clearer.