Azure Active Directory
You can setup Azure Active Directory (AAD) as a user manager for authentication and authorization of tasks after installation of the product.
Once you've installed and configured the product, which you must do using AD or SQL as the identity store, you can change the user manager to AAD. If SharePoint is configured for AAD (such as when integrating with SharePoint Online), and you install the Nintex K2 for SharePoint app, the AAD label is setup and configured automatically, which is recommended. For information on manually configuring Nintex K2 for AAD, see the topic Manually Configure Nintex K2 for Azure Active Directory.