Sure thing, huh_phd. Put simply, nutritionist is not a regulated term. There is no defined curriculum, training, or education required to call yourself a nutritionist. Anyone can call themselves a nutritionist. To be a Registered Dietitian (RD), there is specific coursework you need to complete, The Didactic Program in Dietetics (DPDs), a minimum 1200 hour dietetic internship, and passing of the RD examination which is distributed via the Commission on Dietetic Registration (CDR).

A list of the required coursework can be found here, and this is where I completed both my DPDs and Master's in clinical Nutrition, New York University.