The paper presents a relaxation study of nanostructured compounds of variable composition ZnS_1-xSe_x. The developed ZnS and ZnSe semiconductor nanoelectromechanical chips consist of 1,000 atoms of 5×5×5 unit cells in a sphalerite crystalline structure. Interatomic Zn – S and Zn – Se electromechanical pseudopotentials are calculated with an approximating quasiparticle density functional. Stability of nanochips of variable composition ZnS_1-xSe_x is studied with a molecular mechanics method. It is shown that, generally, nanoelectromechanical chips formation in a matrix of ZnS_1-хSe_х sphalerite crystal leads to slight changes in the total energy and interatomic spacings. Formation of continuous substitutional solid solutions in the sub-lattice B6 of ZnS_1-хSe_х nanochips follows the Vegard’s Law quite well with minor deviations due to transformations of the second and the third coordination sphere in nanochips as a result of B6 component concentration changes. There is a predominant nonlinear destabilizing contribution with a positive deviation of the total energy for х = 0,25 and х = 0,75.