Firstly, make sure you are in 15.4.A.0.23 and above.
1. Head over to this
site. Download the latest build for Nicki.
2. Extract boot.img from the downloaded zip and flash in fastboot.
3. Wipe /data and /cache through CWM.
4. Put the CM11 zip in any storage then flash it in CWM.
5. (Optional) Download GApps from here
. Make sure it's for 4.4.4. Then flash it in CWM.
If you are having root permission problems, download the latest SuperSU flashable zip from here
then flash it in CWM. Disable the default Superuser app (it can be found in Developer Options by tapping the Build Number 7 times) in CM11 and untick the box in SuperSU that states "Respect CM root settings."
That's it. Hope I helped.