This study investigates the function of Mitotic Arrest Deficient 2 Like 1 (MAD2L1) and its role in facilitating NANOG nuclear localization, contributing to chemoresistance in lung cancer. Using both in vivo and in vitro models, we examined MAD2L1 expression in Carboplatin-resistant lung cancer cell lines. The study utilized gene knockdown and overexpression techniques to assess MAD2L1's role in chemoresistance and cell stemness, alongside co-expression analysis and fluorescence staining and CO-IP to explore MAD2L1 and NANOG interactions. Results showed a marked increase in MAD2L1 expression in resistant lung cancer cells, correlating with enhanced cell stemness. MAD2L1 knockdown heightened sensitivity to Carboplatin and reduced NANOG expression, while MAD2L1 overexpression led to increased resistance and stemness. Mechanistically, MAD2L1 facilitated NANOG's nuclear localization, with their co-expression linked to increased cell resistance and metastasis in vivo. These findings suggest that MAD2L1 enhances chemoresistance by promoting NANOG localization, offering insights into potential therapeutic targets for overcoming lung cancer chemoresistance.Copyright © 2025 Elsevier Inc. All rights reserved.