These instructions will work on any FreeBSD install, but you don't necessarily need nano to accomplish it. On a jail on FreeNAS you need nano because the keyboard combinations required to edit the config files cannot be executed on the web gui console.

passwd (set password)
pkg update (update pkg database)
pkg install nano (install nano text editor so you can edit in the browser console)
nano /etc/ssh/sshd_config (edit ssh daemon config with nano)
<ctrl+shift+w> to find text
#change the following fields to listed values and un-hash
   "PermitRootLogin yes"
   "PasswordAuthentication yes"
<ctrl+shift+x> to exit
<Y> then <Enter> to save
sysrc sshd_enable=yes (enable ssh)
service sshd start