To use the Am I Affected scan in the IBM Security QRadar Threat Intelligence app, the required additional license is the IBM Advanced Threat Protection Feed license. This license provides the necessary threat intelligence feeds needed to run the scan effectively and identify potential threats. The IBM Security QRadar Console and QVM licenses pertain to different aspects of QRadar's functionality, while the IBM Watson license is not directly related to enabling the 'Am I Affected' scan in this context.