No. RCON is not offered on a Rising World server at PlayNHost, and its settings are not in Game Settings. Use the panel's Console tab instead: it takes Rising World's server console commands, with no login.
Why is there no RCON?
Rising World's dedicated server guide says RCON is optional and uses a separate port, 4253 TCP by default. For an outside tool to reach it, that port must be one of your server's ports, and your server's ports are assigned by the machine it runs on. The Ports & Network page in the left menu says: "Port numbers are assigned by the machine your server runs on - you can name a port, but not choose its number." So the panel does not show the RCON settings at all.
What should I use instead?
The Console tab. Rising World's server console takes commands such as say, kick, saveall, makeadmin and version, and the developer says these "don't require you to be logged into the server". Type them in the Type a command box, without a slash. A command can take up to a minute to run. Full list: How to use the Console and commands on your Rising World server.
To let a friend run commands without your login, invite them in Team & Roles with the Use the console permission: How to invite friends to your Rising World server.
To run commands on a timer, use Quick Tasks: Send Command takes any console command, and Save World sends saveall. See How to restart your Rising World server every day.
Can I turn RCON on in server.properties?
No. The panel writes the RCON_Enabled, RCON_Password and RCON_Port lines of server.properties itself at every start, so a change you type there is replaced at the next start. Even switched on, RCON would listen on port 4253, not on one of your server's ports.
