Use the rpc.nisd to download all LDAP data to NIS+, overwriting existing NIS+ data.
Assuming all NIS+/LDAP data mappings have been established in the default location (/var/nis/NIS+LDAPmapping), use the following command.
# /usr/sbin/rpc.nisd -D \ -x nisplusLDAPinitialUpdateAction=from_ldap \ -x nisplusLDAPinitialUpdateOnly=yes |
The above would make the rpc.nisd daemon download data from LDAP, and then exit. The LDAP data would be unaffected by this operation.
See the nisplusLDAPinitialUpdateAction attribute on rpc.nisd(4).