I have a custom list with some values. I'm using that list to mimic the cascading drop down found in InfoPath. I'm using List Lookup action to get and display info on the form. Everything is working as expected but I don't want the page to reload everytime I select a value from the first dropdown.
I understand what your going through. I followed this guide Cascading drop downs and Nintex Forms for SharePoint and I have no issues with my forms refreshing at all when you select what you need from the drop downs.
If problem keeps happening let me know and I'll more into it and see what can do.