I have a NAS that I use as a restic target for backups on my laptop and my desktop using sftp.
I then have restic on the NAS do a backup of those repositories to b2.
Restic is encrypted on the NAS.
The backup from the NAS to b2 is also encrypted (with a different password).
Keeping in mind that this is a home scenario is this an ok way to sync my backups to b2?
This sounds like a feasable way of doing backups. Although, personally, I would just use rsync for the backup from NAS to b2. The second encryption should not really increase security if you’re doing it right and the restore from b2 to client in case of a failure of both client and NAS would require one additional step where in my scenario you could just restore directly from b2 to the client.
Seems like a sensible set-up to me. You should also be checking the health of the repository from time to time with restic check and restic check --read-data. Eventually you will also want to forget and prune to remove old data. If it’s automated you also ought to make sure you have a way of checking that backups to the NAS, and copies to b2, are working OK. It’s easy to set and forget 
Thanks to you both.
My main concern was having the repo remain in tact from the NAS to B2.
I’ll have to do a test of retrieving the repo file from b2 and then restoring them to another machine. I’ll update here once I’ve tried it.
If you rsync a repo, it will be totally usable afterwards. I’ve done it many times. As a matter of fact, at home I always do repo checks against the rsynced copy to be sure I catch all possible errors.