I manage to get Neverwinter Nights 2 with Mask of The Betrayer and Storm of Zehir expansions working on Crossover 7.1.2.
I needed to install directx9.0 in the bottle. The installer also asks for .NET 2.0 for the NWN2 Editor.
Tested on Archlinux x86_64 with Core 2 Duo 2.0 Ghz and nvidia 9300M with the nvidia drivers from 177.80 to 180.44. To get it work, I also needed the lib32-nvidia-utils package. The game is playable but a bit choppy even with graphical effects turned off.