You are using the open drivers for nvidia, the best is to install the proprietary ones since nvidia didn't release the firmware and some hardware capabilities doesn't work. Go on the system to preferences > hardware configuration and install the proprietary driver
As I wrote on some forum before, this does NOT fix an issue.
Did you launch TW2 on latest Manjaro or it was just a wild guess (no offense, seriously)?
I manage to launch it, i have to reinstall it after an update for ICU(the last version may have broke the game) and the game launch as normal and can play as normal.
I'm not a nvidia user but i used their card before and i know that the open source driver nouveau (the ones that appear on your log) it's in bad shape. The cards can't go beyond the lowest clock available since there is no fan control and the heat is to much for passive cooling. Also the opengl drivers are better and should improve performance and make the games more stable.
Maybe you are not loading the correct ones on the boot process, this can help you with the drivers if that is the case: