It's essentially the same as you would do for a port-forward from any external host, except your ACL has the allowed host IP in the source field.
Scenario:
Allowed external ip address 192.0.2.5
External IP of router 172.16.1.5
Internal SSH server 192.168.10.5
ip access-list extended ssh-fwd-list
permit tcp host 192.0.2.5 host 172.16.1.5 eq 22
interface eth 0/1
description WAN to Internet
ip address 172.16.1.5 255.255.255.0
ip access-policy Public
ip policy-class Public
nat destination list ssh-fwd-list address 192.168.10.5 port 22