I've got a text file called "HECNODES2.TXT" which I think I must have acquired via this email list somehow, which is in the format that can be imported into decnet_register.
it starts out like this, so you could fairly easily make your own version from the basic nodenames file and a bit of scripting.
!
! DECnet/OSI node name export/import file 3-MAR-2022 12:49:39.21
!
=Type DECnet Node
=Version 1
=All Address Prefix 49::
=DECdns Name Template ???:.???.*
=DECdns Synonym Directory ???:.???
=DECdns Reverse Address Directory ???:.???
=PhaseIV Name Template *
=LocalFile Name Template LOCAL:.*
ERNIE ERNIE {Tower=SC2/NSP/CLNS=1.2}
FNATTE FNATTE {Tower=SC2/NSP/CLNS=1.3}
GOBLIN GOBLIN {Tower=SC2/NSP/CLNS=1.4}