I recently worked on a Nintex Form and Workflow project for a large company who was made up of several smaller subsidiaries. Each subsidiary had multiple offices that were scattered across North America – for a total of 56 offices. This caused problems when trying to publish the workflow.
Update (07-28-15)
I got official word from Nintex support about the issue. Here is what they said.
"A SharePoint limitation has been hit. Workflow XAML failed validation due to the following errors: Exceeded maximum XAML element depth; maximum is 125.
https://technet.microsoft.com/en-us/library/cc262787(v=office.15).aspx
Under dWorkflow limits] / Maximum depth of a workflow sub-step in xaml (workflow complexity).
If you were to try the same workflow in SPD the same error will occur."