This paper presents a numerical investigation on the wave resonance in a narrow gap between two floating bodies in close proximity using a hybrid model, qaleFOAM, which combines a two-phase Navier-Stokes model (NS) and the fully nonlinear potential theory (FNPT) using a spatially hierarchical approach. The former governs the computational domain near the floating bodies and the gap, where the viscous effects are significant, and is solved by using OpenFOAM/InterDyMFoam. The latter covers the rest of the domain and solved by using the Quasi Lagrangian Eulerian Finite Element Method (QALE-FEM). The model is validated by comparing its numerical predictions with experimental data in the cases with linear incident waves. Systematic investigations using incident waves with different steepness are then followed to explore the nonlinear effects on the wave resonance.