I would venture a guess at no, it looks like wix uses its own site templates (like you select from their stuff and pick one) and it seems the whole point of that site is to let people make tiny simple pages without actually learning anything that they can take somewhere else, and I don't even know if you can have a database on their system which is needed for just about any forum.
You need a real server that you can call your own, even if it is a cheap shared environment.