I'm using Nintex Forms for O365 (App Version: NFO 1.2.2.0) and was trying to set up a tabbed interface using the Choice control's Display Format = Option Buttons (See my screenshot of the Control Settings, below).  This is a really cool built-in feature based on this video, however it looks like on-prem SharePoint therein: Create Tab like functionality on your Nintex Forms. 

So here's the problem -- the buttons are NOT rendering in O365, rather it just looks like a typical radio button field.  Is there a workaround to this?  Custom CSS or anything?  I'm new to Nintex so I may have missed a step, so if there's a video out there specific to O365, that would be helpful as well.

Thanks!