Most countries now have laws that distinguish between psychotherapy and coaching. Therefore, psychotherapy is now regulated so that only qualified and certified / licensed professionals in the field can perform and teach it. 

If one is not qualified and certified as a psychotherapist/psychiatrist/social worker/medical professional to use psychotherapeutic methods, then certain NLP techniques and certain problems may not be used or taught. 

For clarification and as a warning: 

All issues/topics/problems that are considered psychotherapy are officially psychotherapeutic illnesses as defined and listed in the current ICD and DSM books. (ICD-10, DSM-5).

For example:  Phobias, traumas, compulsions, depressions, addictions, allergies, etc. are listed in these books and therefore may not be worked on or used or taught in NLP trainings unless the NLP trainer and all participants are officially certified as psychotherapists or similar.

If you ask yourself, what is left to work on in coaching. There are a lot of things to work on, everything that is not in the books. If psychotherapy is defined as a profession that works with people who have a mental illness, then coaching is defined as a profession that works on people with problems where they are mentally healthy.

It follows that:  

Coaching issues/topics/problems are any problems that do not correspond to a defined psychotherapeutic illness.

E.g. grief over the loss of something, bad moods, relationship problems, job applications, nervousness at presentations, bad habits, goal achievement, unhappiness, decision making, dealing with difficult or important people.