We have found and interesting bug/feature in SharePoint 2013. Maybe you are aware, for us it was an easter egg.
Saved list template stores the workflow association, and on the same site it partially carries the workflow to the new list which you created from it.
Steps to reproduce:
You can't manually start but it's there.
If we check the list template file (.stp) as source (you can rename the extension to .CAB and unzip) in the manifest XML, we can see the workflow assosciations in that.
Renamed to .cab:
Open the manifest with Notepad (or alternative):
You can delete this part and pack it back to the CAB, but by default WinZip can't create CAB file, so you may need other programs for that.
Hope it helps!
You should be able to see this in the SharePoint Workflow settings rather than the Nintex workflow gallery for your new list. You could then delete it out of that list.
A better option for lists that you are templating is the Site(Collection) reusable workflow template. You associate it to a content type and then re-use over and over whenever you create a copy of that list from it's template. It also means that you can edit that workflow in a single location and re-deploy it to all instances around the site. Much more manageable.
Does this help?
It didn't appear in the workflow gallery. At least I didn't see it, maybe I will check again on Monday.
I didn't want to reuse that more. I needed a copy of the list itself, but not with the workflow.