If you run (paths stripped)
PsExec64.exe -s vboxmanage showvminfo yourvmname
Does this show a NAT attachment to NIC1 and a (whatever interface) attachment to NIC2? Does NIC1 have a port forward to TCP/22?
I have subsequently installed Hyper-V, so I’m not using these commands any more, but these are the sorts of things I’d check. Alternatively, run
PsExec64.exe -s virtualbox.exe
And then see what’s going on by pointing-and-clicking on the GUI.