You can create or update the ISO's autounattend.xml, and copy the XML block for <DiskConfiguration>. There are many online examples for unattended files that have a disk layout.
If you're already using NTLite's Unattended mode to add other settings, be careful where you insert the extra lines.
Or you can choose to use an Unattended file generator like:
https://schneegans.de/windows/unattend-generator/
If you're already using NTLite's Unattended mode to add other settings, be careful where you insert the extra lines.
Or you can choose to use an Unattended file generator like:
https://schneegans.de/windows/unattend-generator/