In Nintex 2016 Workflows, I want to be able to format some of my own fields in a specific way when I use them in a workflow. Mostly I need to be able to format the "Created by" field as a display name and not a string. How do I do this? 

At the moment, in a Send Notification I format the e-mail like this:

and the output I get is this:

How do I get it to be formatted as the Display Name?