In this article, an nonenzymatic sensor based on Ni(OH)₂/electroreduced graphene oxide (ERGO)-multiwalled carbon nanotube (MWNT) nanocomposites is fabricated via convenient electrodeposition of Ni(OH)₂ nanoparticles on ERGO-MWNT film modified glass carbon electrode (GCE). Graphene oxide (GO) sheets can serve as surfactants to stabilize the dispersion of pristine MWNTs in aqueous solution, rendering a fine coverage of ERGO-MWNT film on GCE during the fabrication process. MWNTs perform as conducting bridges between ERGO sheets to enhance the electron transfer rate in the substrate. By combining the advantages of ERGO and MWNTs, together with electrocatalytic effect of Ni(OH)₂ nanoparticles, the well-designed nanocomposites exhibit excellent sensing behavior towards glucose and hydrogen peroxide (H₂O₂). The linear detection ranges for glucose and H₂O₂ are 10 μM ~ 1500 μM and 10 μM ~ 9050 μM while the detection limits are 2.7 μM and 4.0 μM, respectively. Furthermore, a very high sensitivity is achieved with 2042 μAmM^-1cm^-2 estimated for glucose and 711 μAmM^-1cm^-2 for H₂O₂. These results suggest that Ni(OH)₂/ERGO-MWNT nanocomposites thus easily prepared through a green electrochemical method are promising electrode materials for biosensing. Additionally, good recoveries of analytes in real samples like urine and milk confirm the reliability of the prepared sensor in practical applications.