I dont think this is possible with the equipment modeller or the ENGENERIC command.

It should however be possible if you use a long weld neck flange and then change the SKEY to Nozzle/NZFS.

You would be able to add custom data to the long weldneck, then have that called out on the iso with component attribute mapping.

It does however mean you would need to change all the nozzles in your model