Nan is Former Division Counsel and Associate Chief Counsel, IRS Office of Chief Counsel and former Senior Technical Advisor to the IRS Division Commissioner, Tax Exempt and Government Entities. As lead of the Office of Chief Counsel, she had responsibility for employee benefits, employment taxes, exempt organizations and health care. Nan also has prior experience with the Department of Justice in employment law litigation, service as an Appeals Officer and Revenue Agent, as well as service as adjunct faculty at Georgetown University School of Law.

Nan was twice the recipient of the Presidential Award of Merit for her service in addition to being recognized by the Federal Bar Association in D.C. for outstanding federal legal service. She is a Fellow of the American College of Employee Benefits Counsel.