Nintex Workflow - Want to attach attachment in email from another library

Yes it's possible.

In the action "Send an Email" you can add files to your email, and the will be added as attachment of your email.

You just have to get your file to send. If you are using a SharePoint document library, you can get file with action "Get a file". If your file is on a list item, you can use the action "Get attachment names" and "Get item attachment by name"

I was surprised by the quality of help with academic writing at Academhelpers. It was the first company that did not ignore the attached files and composed a paper without mistakes.