Epitaxial arrays of the InAs1–хNх core-shell nanowires have been synthesized on Si (111) for the first time. The growth of the nanowires with a wurtzite-type crystal structure was demonstrated by a self-induced mechanism using the molecular beam epitaxy with plasma-assisted nitrogen activation. Using the transmission electron microscopy and X-ray diffraction analysis, a volume decrease in the wurtzite crystal unit cell with increasing nitrogen content was revealed.