Looking to use bots as opponents in a gamemode through the bot controller module, but I need to be able to use the nav meshes generated by the game.

Any way to do this?

Not without a binary module.
AzuiSleet made one some time ago, just check out his thread.

That module reads AI nodes - I want to read the nav mesh. Can it do that?

Right, sorry 'bout that.
I don’t think there’s a module for navigation meshes. I guess you’ll either just have to use the nodegraph instead, or create your own system.