Preparation of materials Co3-xNixSn2S2 (0 < x < 3) has enabled the effect of electron-doping on the thermoelectric properties of shandites to be investigated. DFT calculations suggest that in the mixed-metal phases, a lowering of energy is achieved through ordering of nickel and cobalt atoms. For example at x = 1, nickel atoms preferentially occupy one in three of the kagome-like layers of the shandite structure. We wish to exploit the Co/Ni contrast afforded by powder neutron diffraction to characterise the metal atom order in Co3-xNixSn2S2 and for the critical compositions x= 1, 2, investigate its temperature dependence. Although Co/Ni ordering does not enlarge the unit cell, simulations indicate that it introduces new reflections into the neutron diffraction pattern and alters the relative intensities of reflections arising from the underlying trigonal sub-cell.