If you restore from a nandroid then it will put you back to exactly where you were when you took the nandroid (as far as rom, apps, data are concerned - it doesn't back up radios).
If your Ti backups are more recent, you can use them after restoring from the nandroid. Only thing to watch is that you shouldn't restore system settings backed up while running a different ROM, i.e. just restore more recent/missing apps and their data.