As a US Tax Client Specialist, you will serve as the main contact for existing client accounts, responsible for managing changes, supporting clients with tax-related issues, and conducting annual nexus reviews. You'll update tax collection settings, manage client offboarding, and ensure a positive experience. This includes analyzing data, updating tax software, and communicating with clients. You will manage 70 existing clients, finalize 2-4 nexus reviews per month, and handle 20-25 permit and offboarding projects monthly. Additionally, you'll contribute to process improvement and complete 3 hours of work-related education or training per quarter.