["Journal of Consumer Behaviour, EarlyView. ", "\nABSTRACT\nAs generative artificial intelligence (GenAI) continues to transform e‐commerce, platforms increasingly deploy AI shopping assistants to enhance user experiences. However, the impact of AI‐generated information on consumer psychology remains underexplored. This study proposes and tests a decision‐structure nudge—preference‐matching presentation—in AI‐mediated shopping contexts. Across four experiments, we demonstrate that this nudge significantly boosts consumers' decision confidence, with this effect mediated by improved information evaluability. Furthermore, we identify a critical boundary condition: the positive effect of preference‐matching presentation diminishes as product knowledge increases. Our findings extend the digital nudging and AI‐assisted decision‐making literature by introducing a conversational, preference‐grounded choice‐architecture intervention and offer practical guidance for designing transparent and effective AI‐driven consumer interfaces.\n"]