Timemachine backup - restore to new computer

We have a few Mac computers that have been using private Time Machine backups on the ReadyNAS with no issues for quite some time and have even restored files occasionally when needed but now a machine has died and I am trying to restore the backup to a new computer.  Both the old and new computers have Mojave installed. On the new computer when I run Migration Assistant I can connect to the NAS using the credentials that were used on the old computer but it never shows a backup for me to highlight.

Does anyone have some insight as to how I can recover a timemachine backup to a new piece of hardware?