gethashes

(defun gethashes (x &rest y) (dolist (z y x) (setf x (gethash z x))))

(defsetf gethashes (table key &rest more-keys) (new-value)
  (if (null more-keys)
      `(setf (gethash ,key ,table) ,new-value)
      `(setf (gethashes (gethash ,key ,table) ,@more-keys) ,new-value)))

(let ((table1 (make-hash-table))
      (table2 (make-hash-table)))
  (setf (gethash 'a table1) table2)
  (setf (gethashes table1 'a 14) 23)
  (gethashes table1 'a 14))

=> 23