No need to build it seems ; try the following using idlekernel's patched kernel for kali nethunter 3.0 :
- Update to latest stock mmb29q >> from here
- Install custom recovery >> from here
- Install latest cm13 nightly >> from here
- Install open gapps of your choice >> from here
- Don't install supersu, it will be installed with nethunter!
- Boot into system and finish initial setup
- Reboot back into recovery
- Install idlekernel nethunter patched kernel >> from here
- Install full chroot (not sure if needed but i did, gave some errors but ignore that) >> from here
I did not yet have time to do tests but it boots up perfectly and nethunter apps are available so all looks like a good starting point.
Happy hunting !