Nintex Workflow is able to send emails via the Send notification action.
A question often asked is if it can send emails to SharePoint groups or Active Directory groups. The answer is; Yes it can!
There are some things you need to know though…
Send to an Active Directory group
You can use AD security groups, but they must have a (dummy) email value configured or the workflow will fail on this.
The email will only be sent to the direct users in the AD group. Nested AD groups will be ignored.
Send to a SharePoint group
This works about the same as AD groups. The email will be sent to direct users in the SharePoint group, and to direct users of any nested AD group in the SharePoint group. It won’t go into nested AD groups of the AD group though (same as above).
Also, you cannot nest SharePoint groups.
HTH