Currently I don't think that any tool supports capturing Nvidia driver FXAA which is a real shame. The only workaround at the moment would be to run the game in windowed mode or in borderless mode and use windows key+print screen in Windows 8.1 (afaik alt+printscreen works too). Obviously that doesn't work when recording video though.
If it's possible, it would be great to have some kind of workaround for this. I'm pretty sure that AMD's MLAA behaves the same.