Dear, if you are interested in the hotkeys in Ank. And use this great ADDon Customize Keyboard Shortcuts and you will create an new decks with a lot of Subdecks, i know you did not find a shortcut when hovering around the key in the face page of Anki. But Fortunately, you can find a shortcut in the Adding page
press ctrl+D ↦ press ctrl+N
and by the clipboard you well find it easer than using the mouse. 