The use of a multi-state license in Tennessee began in July 2003 as a result of the Tennessee Licensure Compact that was enacted by the Tennessee General Assembly. As a result, Tennessee joined with 20 other states in this compact. A nurse with a current license in one of those states may practice nursing in any of the other 14 states without having to apply for a new license in that state.
The states that are members of the compact are Arizona, Arkansas, Delaware, Idaho, Iowa, Maine, Maryland, Mississippi, Nebraska, New Hampshire, New Mexico, North Carolina, North Dakota, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia and Wisconsin.
See https://www.ncsbn.org/compacts.htm for more information.
Thus a Nurse with a current Arkansas license can practice in Tennessee without applying for a Tennessee license. On the other hand, a nurse with a Kentucky license would have to apply for a Tennessee license in order to practice in Tennessee.
It is important to note that some of the states in the compact can issue a license valid only in that state. In other words, Tennessee may still issue a license valid only in Tennessee, not in Arkansas or Mississippi. They would do this if a nurse works in a compact state such as Tennessee, but lives in a non-compact state such as Kentucky. So, a nurse living in Kentucky and working in Tennessee would have to apply for a Tennessee license, and would receive a license valid only in Tennessee.