I have a Nintex form with different fields.
One of them is called "Mail" to which I type an email-address.
Is it possible with Nintex-workflow to send the entered form-information to the Email-address entered into "Mail"-field?
This is possible. In the workflow you will use a Send Notification action and use the Mail-field as the send to. You will see this under the lookup section when assigning a variable.
Let me know if you need more information.
If you are not storing the "Mail" information in your list however you will need to query the form data in the workflow to extract this information.