Prioritizing Medical Countermeasures for National Security Act of 2023 This bill requires the Administration for Strategic Preparedness and Response (ASPR) to establish a list of categories of drugs that may be necessary to address a public health emergency or threat to the Armed Forces in order to facilitate the development of such drugs. Specifically, ASPR must list categories and classes of drugs that may be necessary to prevent or treat diseases or conditions that are caused by chemical, biological, radiological, or nuclear agents and that have the potential to cause a public health emergency that threatens national security, or that may pose a threat to the Armed Forces. ASPR must share the list with interested parties to incentivize development and speed review of relevant drug applications. The Government Accountability Office must report on the bill's effectiveness in encouraging the development of necessary medical countermeasures.