More states are licensing naturopathic physicians. Thus, completing a correspondence course(s) in these states will not "certify" you as an ND.
I would caution against these correspondence or online degree courses if you are truly interested in becoming a naturopathic doctor (naturopathic physician.) If you live in a licensed state, you would not be able to call your a naturopathic "doctor" or "physician." You have to graduate from an accredited naturopathic medical school and pass board exams in order to be licensed and to practice.
I've read several posts about Clayton College or some other type of correspondence programs advertising naturopathy or naturopathic medicine. If you do your research carefully, you'll see that many of these people do not necessarily intend on being physicians, instead, they work as wellness consultants or natural health consultants.
Good luck!