I am using Nintex forms for Office 365 version 126.96.36.199.
However, when I include the JS file, it doesn't take effect unless I use Nintex Forms web part. If I click on 'new item' or 'edit item' links from the List, it loads the form but doesn't load the JS. When I look into network traffic, I see HTTP 302 for the JS file but response body is empty which obviously leads to no JS code executing.
I tried giving the all permissions to Site Assets folder but it didn't help.
This issue is not just with JS files but also with images. For images, the src remains empty in the rendered HTML if I refer to an image placed in Site Assets folder.
I am suspecting if this is some permissions issue with Nintex forms app setup since I have another Office 365 installation where I see custom JS files loading and executing with New / Edit forms without having to use Nintex forms web part in a separate page.