In searching for a simple solution for seamless using KeyChord and ViperMode, the following functions and setups is derived:

(defun toggle-viper-keychord ()
  "To toggle viper-mode and key-chord-mode back and forth."
  (if (and (boundp 'viper-mode) viper-mode)
      (key-chord-mode 1)
      (message "Key-chord On."))
      (key-chord-mode 0)
	   (message "Viper-mode."))))

(defun key-chord-turn-on ()
  (if (not (window-minibuffer-p))
      (key-chord-mode 1)))

(defun key-chord-turn-off ()
  (if (not (window-minibuffer-p))
  (key-chord-mode 0)))

Then add these hooks for vi-mode and keychord in ‘sync’ (anti-sync):

(add-hook 'viper-insert-state-hook 'key-chord-turn-on)
(add-hook 'viper-vi-state-hook 'key-chord-turn-off)

Lastly pick your favorite key-chord to toggle viper mode and Emacs mode (with key-chord) seamlessly:

(key-chord-define-global "jk" 'toggle-viper-keychord)

– enjoy! ipstone