Order of Basicity of Nitrogen Trihalides
In case of Boron, boron has vacant orbitals which leads to pi back bonding from halides to boron and that concept is used to explain the basicity of Boron. However Nitrogen doesn't have vacant orbitals, hence that pi bonding is not possible from halide to Nitrogen. Consequently electronegativity is used for explanation for basicity of Nitrogen Halides.