Border Enforcement, Security, and Trade (BEST) Facilitation Act of 2023 This bill establishes positions within U.S. Customs and Border Protection (CBP) to review inspection images of vehicles and cargo entering or exiting the United States. Specifically, the bill establishes the position of image technician within the CBP Office of Field Operations. An image technician must (1) review nonintrusive inspection images of vehicles and cargo entering or exiting the United States; (2) assess whether there are indications that such vehicles and cargo contain contraband, illicitly concealed merchandise (e.g., drugs and weapons), or persons seeking to unlawfully enter the United States; and (3) recommend suspicious vehicles and cargo for further inspection by a CBP officer. The bill also establishes the position of supervisory image technician with additional responsibilities, including receiving and reporting intelligence to the National Targeting Center about techniques used by malign actors to transport contraband, illicitly concealed merchandise, and persons seeking to unlawfully enter the United States. A CBP officer shall retain the discretion and final decision-making authority on whether to release a vehicle or cargo or refer the vehicle or cargo for further inspection. The bill establishes annual training requirements for both image technician and supervisory image technician positions, including training on privacy and civil liberties and how to analyze inspection images. Within a year of this bill's enactment, CBP must develop a workforce staffing model for these positions. The Government Accountability Office must validate the model within six months of the model's completion.