It depends on your state. As an RN, you are probably familiar with the RD credential, right? Some states it is illegal to practice without the RD, which is required for that state’s licensure. Other states it is legal for everyone to practice, but you just can’t call yourself licensed. That’s why there are all these nutrition coaching certifications out there to give oneself a title of nutrition expert without going through formal nutrition training since the public doesn’t know the difference.