In the present article, simulation data for copper nanoparticles undergoing acceleration in a Laval micronozzle and then experiencing deceleration in a wall compression layer are reported. It is shown that, at the expense of reduced dimensions of the nozzle and reduced nozzle exit - to - obstacle separation, a sufficiently high impact velocity of nanoparticles can be achieved, allowing the nanoparticles to stick to the obstacle surface with the formation of a coating, like it occurs in a cold spray process. A size effect manifested as the dependence of nanoparticle impact velocity on the problem geometric sizes is revealed, related with the presence of a characteristic relaxation time in the problem.