This could be done with commanders similar to how Athena builds units, tie units to modules and allow commanders to deploy nanoframes to build. Future Wars does something similar in that every builder unit has access to Units build tab and can make select few units like transports and others.
Possibly make the cost of modules 0 but morph time slightly longer than usual.
UI space would be a problem if there isn't a limit to how many build modules you can take unless something like folders are used.
Example being in slot 1 where for Cloakbot Factory the Glaive raider would be is folder 1 is raider units that opens up the regular grid of choices with raider units available there.