Duke Nukem Manhattan Project can render graphics in either Direct3D 8 or OpenGL. Stereoscopic drivers for modern systems (e.g.
nVidia or
Tridef), instead, only support Direct3D 9, 10 or 11. While this seems to mean that there's no way to run it in stereoscopy on a modern system, I found a workaround.
There's an OpenGL to Direct3D 9 wrapper called
Qindie GL. Just copy the included opengl32.dll file into your DNMP directory, use the included .reg file to apply the required registry modifications, set the game renderer to OpenGL and you're ready to go! The wrapper will translate the OpenGL calls to Direct3D 9, which will be intercepted by the stereoscopic drivers, and you will be able to enjoy DNMP in stereoscopy!