In the US there are:

Nurse Practitioners, who have Masters degrees and generally function as a independent practitioner, doing much the same as a GP physician. Nurse Midwives are a subset of the Nurse Prac.

Masters Degree Registered Nurses who function as specialists in such fields as infection control, nursing education and case management.

Registered Nurses with bachelors degrees (4-5 years) (most common), who perform the full range of nursing duties, including emergency room, operating room and critical care.

Registered Nurses with Associate Degrees (2 years), who do general nursing duties.

Registered Nurses with Diplomas who basically did an apprenticeship in a hospital. This program no longer exists, and diploma nurses are (literally) a dying breed.

Licensed Practical Nurses (Vocational Nurses in California and Texas) who go through a one-year program. Their scope of practice is limited; for example, most can issue medication in a hospital, but cannot start an IV.

Certified and Registered Nursing Assistants, who go through a 3-4 month program. They do most personal care duties, and are the ones who are most often seen in nursing homes.

Nursing Aids, who have very limited training.