Issue
The following error shows up when you try to create a package with Package and Deployment tool containing workflow and the forms and views that referenced that workflow.
"Ensure that your workflow is deployed before packaging. The Workflow Setting could not be found."

Resolution
On the environment where you want to create the package, open K2 Designer and edit the workflow that is causing this error. Redeploy the workflow without making any changes, and try creating the package again.
If the above does not resolve the issue, please log a support case with Nintex Support.