Issue
When a new site is created from Site template that used Nintex Forms, within the newly created site, existing forms will not be associated with lists, and will instead use the default SharePoint form.
Resolution
This issue was fixed in Nintex Forms 2010 by adding a cmdlt called : "fix-SiteafterImport"
But in Nintex Form 2013, this cmdlt doesn't exist.The fix is to use SharePoint power shell script as following to update the List content type that is used by the Nintex Form:
$spweb= Get-SPWeb "http://your.site.com"$ListName ="yourListname" $ContentTypeName ="yourContentTypeName" $List = $spweb.lists.TryGetList($ListName)$list.ContentTypes["Item"].NewFormTemplateName= "NFListEditForm"$list.ContentTypes[$ContentTypeName].EditFormTemplateName = "NFListEditForm"$list.ContentTypes[$ContentTypeName].DisplayFormTemplateName = "NFListDisplayForm"$list.ContentTypes[$ContentTypeName].Update()
After running the above script, the new site will open the Item forms using Nintex Forms.