Depends upon what you mean by "control" and or what aspect of nursing you are referring to.
In the United States, individual state boards of nursing control who can become or is nurse, define the scope of practice for nurses, control the profession via the issue, suspension and or revoking of a license. All these are via state statues and the board's interpetation nurse practice acts.
Hospitals control the nurses within their employ by what is commonly known as nurse practice acts,which can vary by hospital or clinical setting. Such practice acts define everything from perhaps nurse dress codes, to what duties and functions a nurse performs within the insitituion, rules and statues governing nurses as they practice within or on behalf of the hospital.
Federal regulations by and large defere to a duly licensed (by a state) nurse as the government does not have an equal body for regulating nurses. However via various laws, regulations and programs such as Medicare and Medicaid the federal government does have some influence over nursing practice. Also of course since nurses administer and have access to certian classes of drugs, the federal government has influence there as well.
Finally there are various professional bodies that impose as conditons of membership certian qualifications and have rules regarding nurses, schools of nursing and other aspects of the practice.