Electronic structure calculations are performed to characterise the structures, energies, and spectroscopic data for a series of four-coordinate tris(carbene)borate {NiNO}(10) complexes. There is excellent agreement between the computational and experimental results for known complexes, allowing for structure-function relationships to be delineated. Calculations that provide insights into the synthetic accessibility of nickel(iv) nitrides by oxygen atom abstraction from these complexes are also reported.