Most states have licensed or certified dietitian status, and this status is often transferable between states. This process is entirely separate from the registered dietitian requirements of the Academy of Nutrition and Dietetics. Requirements for licensure or certification vary by state.
After passing the national Registration Examination for Dietitians, if you wish to practice in Wisconsin you can become a Certified Dietitian (CD), a status required by most employers. Contact the Wisconsin Department of Safety & Professional Services for details.
If you wish to practice outside of Wisconsin, you should investigate the certification or licensure requirements in the state where you plan to practice.