URL fetch - JSON object

Hey there,
I’m a complete Javascript newbie. I’ve worked with matlab previously, but nothing more.
My goal is to use Moobot(a twitch chatbot) to display the full name of a chess member in a twitch chatroom
This is the Moobot inputs page:

I.e. As the command stands currently, it would output: Random Bloke
In future I’d give the command user the ability to change which chesscom member they would like the name of.
Is there anyone who can give me some advice on how to do this?