I'm trying to convert an existing SharePoint Designer 2013 Workflow to a Nintex Workflow.  The current workflow contains the following step:  

If CurrentItem:HTML FIle Type equals OneNote.Notebook

I am unable to find "HTML File Type" in the "Set a condition" action in the Nintex Workflow designer in any of the different (list ,resusable, site collection reusable) design surfaces.  How do I "enable" it?  Or what can I do instead to achieve the same functionality?

This is in a SharePoint 2016 on-premises