I though on sharing these steps on adding a Palo Alto appliance into Orion just in case anyone is having a problem.
Step 1 - Enable SNMPv3 on the Palo Alto appliance with the following settings
Create the SNMP view and use this exact OID "184.108.40.206.6" and Mask "0x80" (This information was provided by Palo Alto's tech support).
Once you created the view, you will need to create the SNMPv3 user (use your own password for Auth and Priv, they can be the same if you want)
click o.k and "Commit" changes on the appliance. (save configuration).
Step 2 - Add the Palo Alto host into Orion.
When adding the host enter these settings only under SNMPv3 Credentials.
Leave "Read / Write SNMPv3 Credentials" blank.
Click "Test" and you should get a "successful" message.
I hope this help.