We have determined the electronic structure near the band gap of colloidal 2H-MoS2 nanosheets with a thickness of 1-2 monolayers by a combination of potential-modulated absorption spectroscopy (EMAS), electrochemical gating (ECG) and differential pulse voltammetry (DPV). We identified the edges of the conduction and valence band of the direct transition in the monolayers at -1.18 V and 0.77 V vs. Fc/Fc + respectively, yielding a band gap of 1.95 eV, i.e. an excitonic binding energy of less than 0.1 eV in the high dielectric environment of 0.1 M n-Bu4NPF6/CH3CN. For the bilayers, we found an indirect band gap of 1.55 eV with the valence band edge located at 0.37 V. The as-synthesized 2H-MoS2 nanosheets are n-doped and show strong bandgap renormalization effects upon electrochemical oxidation and reduction. We identified two separate band nesting transitions that utilize points in the conduction band with roughly the same energy as the conduction band edge (-1.2 eV). While the oxidation of the valence band is irreversible, we find the reduction of the conduction band to be mostly reversible over a large potential range. These results indicate that colloidal chemistry affords high-quality 2H-MoS2 nanosheets with a well-preserved electronic structure and potential applications in reductive electrocatalysis, e.g., for the electrocatalytic hydrogen evolution reaction.