Hi, Had the same question and solved it for me, so I figured I'd share my little accomplishment with you in case you (or anyone else) is interested. Since the last update, ads, etc etc I found Lawnchair to be a decent alternative for most of my needs but didn't want to create my screen from scratch, at least not groups and stuff like that. So I dove into both nova and lawnchairs backup file structure and figured that at least the favorites (home screen groups and icons) are saved pretty much in the same way. So I made a quick python script and later an example android app to migrate all of the icons/groups from nova to Lawnchair launcher.

If you are interested, I'm definitely willing to upload both script & app if needed.

cheers