Is this possible or has someone figured out a workaround to get files or scanned documents into Nintex Mobile App as an attachment?
The new Nintex App Studio will allow you to have links out to such things. I believe it is coming out shortly if it is not already out.
Is this the kind of functionality you're looking for?
Yea, It is already released. Nintex App Stdio will let you upload different kinds of documents, videos, images and you can generate app. You can use all uploaded documents in offline mode as well.
Unfortunately, we do not have a centralized MDM and our users have been just using and downloading Nintex mobile. It would be difficult for me to identify who is using the mobile app or not to push using AppDeploy.