In the present study, 0.05 wt.% of Ni -coated multi-walled carbon nanotubes ( Ni -CNTs) were successfully incorporated into the 95.8Sn–3.5Ag–0.7Cu solder using the powder metallurgy technique, to synthesize a new lead-free composite solder. Its mechanical property (in terms of hardness) was investigated at room temperature using the nanoindentation method. The results revealed that the nanoindentation hardness increased by 14.3% with the incorporation of 0.05 wt.% of Ni -coated CNTs. This observation is in good agreement with the microhardness test results. Moreover, the addition of Ni -CNTs improved the creep resistance of the composite solder. The test results established that nanotechnology coupled with composite technology in electronics solders can result in the enhancement of mechanical properties. These advanced interconnect materials will thus benefit the microelectronics assembly and packaging industry.