Entity Type 1: Individuals who render health care; e.g., physicians, dentists, nurses, chiropractors, pharmacists, physical therapists and sole providers. Incorporated individuals may obtain NPIs for themselves (Entity Type 1 Individual) if they are health care providers and may obtain NPIs for their corporations (Entity Type 2 Organization). A sole proprietorship is an Entity Type 1 (Individual). A sole proprietorship is an Entity Type 1 (Individual). (A sole proprietorship is a form of business in which one person owns all the assets of the business and is solely liable for all the debts of the business in an individual capacity. Therefore, sole proprietorships are not organization health care providers.) Note that sole proprietorships may obtain only one NPI. Sole proprietorships must report their SSNs (not EINs even if they have EINs). Virtually any health care provider could be a sole proprietorship, including most of the examples listed in Entity Type 2.
(courtesy of https://nppes.cms.hhs.gov/NPPES/Help.do?topic=SelectEntity)