On Storage Adapters I only see the "Devices" of NAS 1 and our SAN, not NAS 2.
NAS 1 and 2 are simple NAS without masking capabilities, you can just select username and password or no authentication for iSCSI.
I tried mountin one of the 3 LUNs from a Windows host in order to check if it is working, and it is, without problem. Once the connection is established the NAS 2 shows an active connection for the LUN. And when I configure the ESXi hosts, it does so, too.
(of course I severed the connection from the Windows host after the test!)