I've noticed some squirrelly behavior when I have both a SharePoint ListView Web part and a Nintex List Web Part on the Same Page. Even after I connect them via the Connect Function on the Nintex Web Part, the Nintex List Web Part is not always in sync with the SharePoint ListView Web part.
Also not clear on the initial settings--Any way to make the Item ID more dynamic? Update on Fly? I've been putting 1 as the ID. What if I delete that record--Do I physically need to reedit the web part. Normally be clicking on one of the items it re-syncs--but notice after filtering the Nintex Web part is showing a non-displayed record.
Other funny stuff happens when I alter the ListView Web Part by editing the Url for various filters. At this time when I click the on the Item in the ListView Web Part, the Nintex List Web Part displays but all items on my ListView Web Part disappear.
No Cordination on Filtered URL:
Url is filtered by Name:
After Clicking on Second Item Co-ordination but all items MIA:
Gave up on that beast.
We tried a number of things with Frames just couldn't get the sync to be reliable. If you don't need the Nintex form you could try something with REST APIs. I've used a combination of REST API's and D3 to sync data from a dropdown.