Engineering electronic properties by elemental doping is a direct strategy to design efficient catalysts towards CO2 electroreduction. Atomically thin SnS2 nanosheets were modified by Ni doping for efficient electroreduction of CO2. The introduction of Ni into SnS2 nanosheets significantly enhanced the current density and Faradaic efficiency for carbonaceous product relative to pristine SnS2 nanosheets. When the Ni content was 5 atm %, the Ni‐doped SnS2 nanosheets achieved a remarkable Faradaic efficiency of 93 % for carbonaceous product with a current density of 19.6 mA cm−2 at −0.9 V vs. RHE. A mechanistic study revealed that the Ni doping gave rise to a defect level and lowered the work function of SnS2 nanosheets, resulting in the promoted CO2 activation and thus improved performance in CO2 electroreduction. Nickel in thin tin: Atomically thin SnS2 nanosheets were modified by Ni doping for efficient electroreduction of CO2. Introduction of Ni into SnS2 nanosheets enhanced current density and Faradaic efficiency for carbonaceous product relative to pristine SnS2 nanosheets. When the Ni content was 5 at. %, Faradaic efficiency was 93 % with a current density of 19.6 mA cm−2 at −0.9 V vs. RHE.