Hi @johnreece
At this time you can have both Nintex Workflow for 365 and Nintex Automation Cloud working on the same lists and libraries on any site, there is no restriction from Nintex's side on this.
Kind regards
Jake
@Jake thank you for the input.
I'm not clear on how to open a workflow cloud form from the library if the 365 app is installed.
John
Hi @johnreece
There are 3 apps that can be in use here;
Nintex Forms for Office 365
Nintex Workflow for Office 365
Nintex Automation Cloud
To override out of the box SharePoint forms you need to use Nintex Forms for Office 365, this allow you to use Nintex forms to create content in the library/list.
Once a record exists in the list/library then a Nintex Workflow app can react to that.
Nintex workflow for 365 is installed on a site level
Nintex Automation Cloud is a stand-alone app that can be attached to whole tenants/site collections
NAC (Nintex Automation Cloud) does have a stand-alone capability when it comes to forms so you can create a 'start form' for a workflow, this however at the moment cannot be used to override a SP list/library form behaviour like the Nintex Forms for 365 app can, It is however possible to link/embed this form if you want to use it on SharePoint but as the NAC in considered an external app we don't have the level of control Nintex Forms for 365 has.
A regular solution that I use all the time is to use Nintex Forms for 365, forgo Nintex workflow for 365 and use Nintex Automation Cloud as the workflow engine.
There is an app to help integrate Nintex Automation Cloud designer into 365 please see below.
https://community.nintex.com/t5/Nintex-Workflow-Cloud/Nintex-Automation-Cloud-App-Installation-for-SharePoint-Online/ta-p/226358