Tin disulphide (SnS2) as layered metal dichalcogenide is a promising material for Na ion storage at sodium battery electrodes. This structure allows controlling the interlayer spacing to accommodate more Na ions and increase the migration rate of Na ions in materials. This research used a Density Functional Theory (DFT) to study the effect of interlayer spacing on the binding energy of the Na ion intercalation process. In addition, this study observed the possible migration pathway for Na ions in SnS2 and the barrier energy of each path using the Nudged Elastic Band (NEB) method. The result shows that interlayer expansion can improve intercalation kinetics and decrease the barrier energy of Na ion migration which is the main constraint on sodium batteries' performance. This study provides an overview of ion intercalation and migration for electrode application in layered materials.