When working with VNC payloads, the Metasploit framework need vncviwer to be installed on the machine. Since Apple includes a VNC Client by default with OSX lets create a simple bash script that will call on the hos:ip combination that Metasploit uses with vncviwer so we do not have to fight with XQuatz and X11 to get one running on OSX:
echo '#!/usr/bin/env bash' >> /usr/local/bin/vncviewer
echo open vnc://\$1 >> /usr/local/bin/vncviewer
chmod +x /usr/local/bin/vncviewer
This will allow us to call from the terminal a connection to a VNC Server like:
vncviewer 192.168.1.120:5901