Nintex Automation Cloud - Add attachment to an item on-prem

Is it possible to have an anonymous form in Nintex Automation Cloud with an attachment field that when summitted, the workflow will create the item in SharePoint on-prem (SharePoint 2016), then attach the attachments from the form to the newly created item. 

Using Nintex Gateway I am able to create the item in the on-prem list, but I cannot figure how how to add the attachments from the form to the new item in on-prem.

Any help would be appreciated.

Thanks.