There are just a handful of psychiatrists in all of western Nebraska, a vast expanse of farmland and cattle ranches. So when Murlene Osburn, a cattle rancher turned psychiatric nurse, finished her graduate degree, she thought starting a practice in this tiny village of tumbleweeds and farm equipment dealerships would be easy.

It wasn’t. A state law required nurses like her to get a doctor to sign off before they performed the tasks for which they were nationally certified. But the only willing psychiatrist she could find was seven hours away by car and wanted to charge her $500 a month. Discouraged, she set the idea for a practice aside and returned to work on her ranch…

But in March the rules changed: Nebraska became the 20th state to adopt a law that makes it possible for nurses in a variety of medical fields with most advanced degrees to practice without a doctor’s oversight. Maryland’s governor signed a similar bill into law this month, and eight more states are considering such legislation, according to the American Association of Nurse Practitioners. Now nurses in Nebraska with a master’s degree or better, known as nurse practitioners, no longer have to get a signed agreement from a doctor to be able to do what their state license allows — order and interpret diagnostic tests, prescribe medications and administer treatments.