Enhancing the Security of the U.S. Pharmaceutical Supply Chain Act of 2020 This bill provides tax credits for manufacturing certain priority medicines and establishes an expedited review procedure for drug manufacturers seeking to transition from foreign manufacturing to domestic manufacturing. The Department of Health and Human Services (HHS) must publish annually a list of priority drugs and active pharmaceutical ingredients that (1) are necessary for use in a public health emergency, (2) are at high risk of becoming in short supply, and (3) have a vulnerable global supply chain. The bill provides a tax credit for 50% of a manufacturer's direct and indirect costs incurred in a taxable year for the production of a drug or active ingredient that was on this list in any of the five preceding years. Furthermore, the Food and Drug Administration (FDA) must expedite the review and approval of a supplemental application that seeks to transfer manufacturing of an already-approved drug or active pharmaceutical ingredient to a domestic establishment. (A supplemental application generally involves a change, such as a manufacturing change, to an existing application for FDA market approval.) The bill imposes various requirements for this expedited review, including a deadline for the FDA to take action on such a supplemental application within six months of submission. HHS shall also establish the Facility Transfer Working Group to assist with evaluating such applications and provide advice and feedback to applicants upon request.