In this work, we present the modal analysis and the design consideration of a hybrid plasmonic waveguide (HPWG) based sensor. The device has a very simple structure and uses Silicon nitride (SiN) technology compatible with CMOS foundries, a top cladding of SiO2 and a thin gold layer. This noble metal is suitable for its stability, high sensitivity and its capability to propagate plasmons in the visible range. In order to obtain the best design, the article analyzes the behavior of the hybrid modes present in the structure for the visible and part of NIR spectrum region (400–1000 nm band), as well as the impact of oxide and gold on sensing performance. A compilation of the best potential cases with higher performances are presented from simulations based on 2D-FDTD solver. Sensitivities higher than 900 nm/RIU and FOM greater than 20 RIU−1 are reported. Finally, a discussion of our results and a roadmap to conduct similar designs are also presented.