We elaborate InP(1-xA)s(x) nanowires by vapor-liquid-solid growth, with small and short composition oscillations produced on purpose with a constant time period. The lengths of these oscillations, measured in single wires by transmission electron microscopy, give access to instantaneous growth rates and their distribution reveals the nucleation statistics. We find that these statistics are strongly sub-Poissonian, which proves that the nucleation events are anticorrelated in time. This effect, specific to nanovolumes, efficiently regulates nanowire growth. We explain it by the rapid depletion of the catalyst droplet in group V atoms upon forming each monolayer of the nanowire.