Soon after the OnePlus One was released, its pre-installed apps were ported to other devices running CyanogenMod. However, the ROM related features like the lockscreen still remained an exclusive to the handset.
Now, owners of Nexus 5 can enjoy all the features of CM11S on their handset as the ROM has been ported to it.
The ROM is based on Android 4.4.4 and does not have any major bugs whatsoever. All the new features in CyanogenMod 11S like the lockscreen and the theme manager are also working perfectly on the Nexus 5.
The developer has also changed the DPI of the ROM to 445 to fit in more information on the screen, though this might lead to some compatibility issue with some apps.
Installation is like any other ROM and requires Nexus 5 owners to have an unlocked bootloader with a custom recovery installed. You can head over to this XDA thread for the download link.