Understanding how different debriefing formats impact learner’s cognitive load is crucial for designing effective post-simulation reflection activities. This paper examines cognitive load after post-simulation debriefings facilitated either by a human instructor or a generative AI Chatbot. In a controlled study with N = 45 educational science students, 23 participants engaged in a lecturer-facilitated debriefing, while 22 completed a chatbot-guided session. Cognitive load was assessed across intrinsic, extraneous, and germane dimensions. Results revealed no statistically significant differences between the two debriefing methods. Future research should examine AI-led debriefings with larger samples and employ complementary measures of cognitive load to provide a more comprehensive understanding.