All right, based on what I found online getting from NAT type C to NAT type A requires that you setup port forwarding to your switch. In a corporate environment I'd not recommend this setup, so continue at your own responsability.
According to the Nintendo website you need to forward UDP 1 through 65535. But I'd very much like to discourage that. That's pretty much saying all UDP ports need to be forwarded to the switch. Instead, try with the port ranges mentioned in this video:
https://www.youtube.com/watch?v=JW7sSOQOyYE
And according to this Reddit post it's 45000-65535 UDP:
https://www.reddit.com/r/NintendoSwitch/comments/6qjhjy/i_have_figured_out_the_actual_range_of_ports...
First setup a static IP for your Nintendo Switch in Security & SD-WAN > DHCP (make sure the IP you choose falls inside the subnet you use, but outside the DHCP range):
Then setup port forwarding in Security & SD-WAN > Firewall: