Can I setup a secondary nameserver for my Linode

I'm pretty sure Linode has disabled AXFR, at least I'm not able to grab any zone data from their nameservers. If that's the case, it means that what you're describing wouldn't be possible.

You could do the reverse - use your NS as the primary, and then create slave zones in the DNS Manager. That process is documented here (step 6):

https://linode.com/docs/networking/dns/dns-manager-overview/#add-a-domain-zone

EDIT: Looks like I was wrong, if you click the Settings link on the far left (under the SOA row at the top of the page for the zone) there's a Domain Transfers field where you can add up to six IP addresses that are allowed to AXFR the entire zone. I don't have any domains on Linode DNS to test myself, but in theory this should work for you.