The realistic nanostructures of pure, Cr and Te substituted MnSe nanostructures are simulated successfully using density functional theory with B3LYP/ LanL2DZ basis set. Using calculated energy and chemical hardness, structural stability of MnSe nanostructures are discussed. Dipole moment and point symmetry of pure, Cr and Te substituted MnSe nanostructures are also studied. The electronic properties of MnSe nanostructures are discussed in terms of electron affinity, ionization potential and HOMO-LUMO gap. The present work provides the information for tailoring MnSe nanostructures with the incorporation of impurities to improve the structural stability and electronic properties, which finds its application in spintronic devices, solar cells and electrocatalysts.