Vinny Gharini‌ , The workflow process diagram is a feature of Nintex on-premise and its not yet available for Office 365.

To check the workflow history in Office 365 ,

On the item ( the one you want to check the workflow history for ) , click on ..., 
Then click on Advanced followed by clicking the Workflows.
 This page  you will see all the workflows that are running or have completed.
Click any of those to see the workflow history.

Currently that not exist on O365.

Although it was asked by many of us.

Add your votes here >>> In O365 Add Workflow Graphical View(View Flow) in RunTime – Customer Feedback for Nintex }

Hi Vinny Gharini‌,

I think you might be interested in checking on the latest from Nintex Hawkeye.  Especially with the highly anticipated release of the Hawkeye Inventory Lens.  Check out the link below and let me know if that might help here for you!

Hi, 

what ‌ wrote is the solution best matching your needs. If you are running Nintex Enterprise subscription then you have an access to Hawkeye tenant as well. The Inventory Lens are now in advanced preview program, but it was said that before the end of the year should start rolling out to tenants. Will see how it will go

If you find any of the above answers as correct please mark it so that other users will know there is a solution here.

Regards,

Tomasz