Currently system names can only contain alphanumeric, hyphen, and underscore characters. Spaces can be included in system tags, however, it is the system NAME that is used if a system is assigned to created a swimlane.
This means that system names that should have spaces either have no spaces or underscores.
The fact that it looks a bit "ugly" is a blocker for some users adopting Promapp and I have been asked to add some of the systems as roles instead because it looks nicer (see example attached).
System names should be able to be inputted as they are seen and written in other contexts.
https://help.nintex.com/en-US/promapp/Admin/Systems.htm
With the transition of Promapp to Process Manager, even your own System name will have to either be ProcessManager or Process_Manager when referenced as a System and then tagged as Process Manager. I've attempted this and couldn't get it to read the System and changed it back to Promapp so it referenced the System accordingly.