[Nova Launcher] JackDSRS:
Yes. But better hang on, its gonna be a bumpy ride. Difficulty level, moderate to weird. This will use drag and drop from the App drawer to the home screen. No root, no programming, no other apps. All Nova.

Lets presume you've set up Nova to NOT allow you to duplicate shortcuts in your App drawer.

To make this easier, add an empty panel to your home screen for a workspace and switch back to the Nova settings. In the App drawer, create an empty folder, say Junk. Go back to the App drawer and you'll find it there. Drag it left or right off the edge of the App drawer and onto the home screen. This will allow us to create duplicates of the apps we want. Use drag and drop from the App drawer to the HOME SCREEN folder fill it with apps you want.

When you're done, go back in the App drawer and look in the Junk folder you made. Magically, its filled with the apps you added on the HOME SCREEN folder.

Now go back to the Home Screen. Make sure the Junk folder is closed. Long press the icon, and press the X to...remove the folder. No kidding.

Go back into your App drawer and your Junk folder will still be there. Why? All we deleted was the SHORTCUT to the folder.

Okay, repeat the process to create a folder called Test. This time, just add whatever apps you want, but you'll see that the folder Junk is one of your available choices. Add that to the Test folder. Take a look. You now have a folder in a folder. All we did is put a shortcut to the folder into the Test folder. Press the Junk folder and it opens like a...well...folder in a folder.

NOTE: You can only do this while the two folders are on the main first Apps screen. Also, if you want to customize the appearance of the sub folder, it has to be done in the App drawer before its placed in the main folder.

Now drag and drop the Test folder onto your home screen. You now have a folder in a folder. You can drag that where ever you want.

I'm not sure how many levels you can nest, but I wouldn't push it past one, although you could have several folders in a folder this way.

And check this out: As long as these are somewhere in your App drawer, you can repeat this drag and drop on as many panels as you have or as many spots on the dock you have available. You can even delete them off of the home screen and still drag and drop them back onto it from the App drawer.

Also, if you modify the swipe actions of the folder on the Home Screen, it'll be retained on the App drawer version even though it won't show it. If it's on the sub folder though, you'll want to do it while its outside of the main folder.

You can also use this method with heavily modified, pain in the butt to reconstruct shortcuts as mini-backups and for frequent reuse.

Finally, since its all native Nova, its all backed up and restored with the native Nova backup.

I've used this since Nova 7. Never thought of posting it here.

Caveat: You can't drag or move an existing folder into the App drawer. By that, I mean one that we didn't create using this wacky process and only created directly on the home screen. But if its just the folder, you can replicate it in the App drawer, then replicate the process with the contents of the home screen, giving you reusable mini-backups to mod or duplicate as you see fit.

On the upside, you can move your completed folder in a folder to any other tab in the App drawer when you're done. If you need to change the appearance of the sub folder, remove the main folder from the tab back to the main Apps tab, uncheck the sub folder from inside the main folder, change its appearance there, add it back in, and re drag it to the home screen. Then you can move the whole shebang back to the tab you had it in.

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In my pics and vid samples I created a main folder called Messaging and added 3 apps to it.

Then I created another folder called "Oh, for..." and added one stock app to it and two pre-saved customized/specialized Hail shortcuts.

"Oh, for..."'s folder icon was changed, then the folder was added into the Messaging folder.

Then the Messaging's folder icon was changed.

The Messaging folder is moved to a tab where I keep all my custom mod, hard to replace re-useable shortcuts. Then the shortcut is dragged to the homescreen.

Pics 1-4 are snippets of the process. Vid 5 is proof of concept that a folder dragged to the home screen can safely be deleted as long as the original is in the App drawer. Vid 6 is the tutorial folder in a folder results using my Messaging and "Oh, for..." folders showing how they work. Vid 7 is a sort of faux multi folder mimic created with Popup Widget. Its an interesting alternative to consolidating functions in a single place, instead of a folder.

Let me explain "Oh, for..." I really only use Messenger to talk to one person, and every conversation makes me wonder where humanity's gene pool is swirling off to. So the zipped lips are a Hail shortcut to freeze and disable Messenger altogether when I'm out of aspirin. The unzipped lips are for Hail to unfreeze Messenger without opening it ("blindfold and cigarette" mode), and the regular Messenger app when my life has been too much sunshine and daisies.

All my icons are originals or insanely upscaled images, shopped to hell and back, (like those lip textures belong to my headache-inducing contact), then scaled back down to 512x512, so I can waste hours or days on micro masterpieces for no one but myself because talking to a ditzy blonde, with those lips, is one of the few other meager entertainments when you get really old. That and medication time.

Jack