Mitochondrial dysfunction is a hallmark of aging that elicits adaptive nuclear responses, yet how chromatin remodeling is coordinated under stress remains unclear. Here, we uncover a phosphorylation-dependent mechanism by which mitochondrial stress regulates the activity of the NuRD (nucleosome remodeling and deacetylase) complex via LIN-40, the Caenorhabditis elegans homolog of mammalian MTA proteins. Mitochondrial stress triggers dephosphorylation of LIN-40, enhancing its interaction with the transcription factor DVE-1 to activate the mitochondrial unfolded protein response (UPR^mt) and chromatin remodeling. Phosphorylation of LIN-40 is mediated by p38 MAPK/PMK-3 and reversed by PP1c/GSP-2. Furthermore, the LIN-40(T654D) variant abolishes mitochondrial stress-induced lifespan extension. These findings establish a direct link between mitochondrial stress signaling and chromatin remodeling via NuRD, revealing an evolutionarily conserved strategy to coordinate cellular resilience and organismal longevity.