The combustion of cellulose nitrate in ballasted mixtures containing an organic binder and nickel hydroxycarbonate or silver carbonate as precursors resulted Ni or Ag nanoparticles. The formation of Ni and Ag nanoparticles from flameless combustion of cellulose nitrate was monitored by time-resolved X-ray diffraction. During the formation of the Ag nanoparticles, the diffraction patterns exhibited only signals from decreasing amounts of the precursor and newly simultaneously formed 20-30nm silver particles. It was detected that in the systems with Ni precursor the formation of the Ni 5-10nm crystals proceeded by some 2-3s diffraction-silent intermediate states of the whole system.