Me. Rev. Stat. tit. 32, § 2101

The State Board of Nursing is the state regulatory agency charged with protection of the public health and welfare in the area of nursing service. In order to safeguard the life and health of the people in this State, an individual who for compensation practices or offers to practice professional nursing or practical nursing in this State shall submit evidence that the individual is qualified so to practice and that individual must be licensed. It is unlawful for an individual not licensed under this chapter to practice or to offer to practice professional or practical nursing in this State; to use a sign, card or device to indicate that the individual is a professional registered nurse or a licensed practical nurse; or to hold oneself out to the public as a professional registered nurse or a licensed practical nurse.