Nesting folders and hiding apps have been two of the more popular glitches in iOS over the years, and they're making a return in iOS 8.
Nesting folders actually still works exactly like it did in iOS 7.1:
Create a folder with at least two apps you want to hide
Put two apps next to each other on the home screen
Place one app over the other to create a folder
When the folder appears, quickly grab the folder you created in step 1 before the screen zooms into the folder
The screen should now zoom into the folder you created in step 3 while you're still holding the original folder, drop your first folder in there and release it.
Hiding an app is a little different than it was in iOS 7:
Fill your home screen with apps
Highlight the app you want to hide and move it to an app on the home screen to create a folder, but don't let go
Move the app out of the folder and down near the dock
When the folder screen disappears, drop the icon in the dock
That should hide the app from your screen. You can still launch it from Spotlight, and the app will reappear if you restart.
How to create nested folders and completely hide apps in iOS 8 | TUAW