We have methodically investigated the structural, spectroscopic, local atomic structure and magnetic properties of aquatic Zn1-xNixS (0≤x≤0.04) nanocrystals. The structural study of synthesized samples are observed by X-ray diffraction datas with Rietveld refinement. Proficient decrease of lattice parameters and inter-planar spacing are determined on Zn1-xNixS nanocrystals. The nanocrystalline microstructure is identified by high resolution transmission electron microscopy. The sphalerite morphology of doped samples are observed by scanning electron microscopy. Shrinkage of energy band gap is observed for doped nanocrystals. Defect formation due to doping of Ni ion is observed by photoluminescence spectroscopy with cyan color emission. X-ray absorption spectroscopy is employed for identification of local structures surrounding of Zn and Ni sites of Zn1-xNixS nanocrystals. Extended X-ray absorption fine structure investigation evidenced the existence of nanocluster within the lattice of Zn1-xNixS nanocrystals. X-ray absorption near edge structure studies confirmed incorporation of Ni2+ in ZnS lattice of Zn1-xNixS nanocrystals. The single pre-edge feature at Ni K-edge is not relying on concentration of Ni dopant in Zn1-xNixS nanocrystals. The presence of interstitial Ni is identified by significant fraction of Ni-Ni scattering paths on doped samples. Zn1-xNixS nanocrystals exhibit defect persuaded paramagnetism at room temperature.