You can't do it directly in AS&R, but here's a three step work-around
- Use the preset 'Add text <Custon text 1> to the beginning of <Tag 1>
- Set Tag 1 to Track#
- Set Custom text 1 to untitled #
This will change the <Track#> to "untiltled #x"
Then use the present 'TOY: Copy tag command'
- Set Tag 1 to Track#
- Set Tag 2 to Title
Lastly, to restore <Track#> back to what it was, use MB's Tools > Tagging Tools > Renumber Tracks
Test this on a few tracks before doing a lot of tracks. And make backups of the test tracks before starting.