Soybean cyst nematode (SCN, Heterodera glycines) causes substantial yield losses by inducing the formation of specialized feeding structure called syncytia, which arise from extensive reprogramming of host root cells. Despite their pivotal role in SCN parasitism, the molecular mechanisms governing syncytium formation and function remain poorly understood, largely due to the technique challenges in precisely isolating these rare cell types. Here, we employed single-nucleus RNA sequencing (snRNA-seq) to generate a comprehensive, high-resolution transcriptomic atlas of SCN-infected soybean roots, comparing two resistant cultivars (PI 88788 and Forrest) with a susceptible cultivar (Williams 82) across multiple infection stages. By leveraging the well-characterized syncytium marker GmSNAP18, we successfully identified and transcriptionally profiled syncytial cells, and validate the spatial expression of known SCN-resistant genes. Our analyses revealed strong induction of resistance-associated genes specifically enriched in syncytia from resistant cultivars. Functional validation further demonstrated that overexpression of three novel candidate genes significantly suppressed SCN development. Pseudotime trajectory analyses traced syncytium development back to procambial cell origins, uncovering distinct, cultivar-specific developmental pathways. Collectively, this work provides a foundational single cell transcriptomic resource, advances our understanding of syncytial biology and SCN resistance mechanisms, and identifies promising molecular targets for engineering nematode-resistant soybean varieties.