I need to find a more advanced nutrition course. I've never taken a basic one, but I'm already very experienced.

NASM, Ace, ISSA and other basic nutrition courses seems to be very basic. I need to find a course that is more advanced for someone who already is very experienced helping clients with nutrition. I don't have a basic nutrition cert. but I don't want to be wasting my time paying for, and studying things I already know. Any suggestions on how to approach this situation?