The ability to import Provider Users in mass is available with the Subcontractor Employee Role import type:
The Subcontractor Employee Role Import type represents Provider Users. This import will allow for the addition of new Provider Users and updates to existing Provider users. The Subcontractor Employee Role Import screen includes the downloadable import template spreadsheet and all of the import mapping information.
Some mapping information included with new import type include User Organization, Username, Password, Active, Permission Group, First and Last Name, Address, Phone, Time Zone, Accounting ID, Language, and Distributor.