Nanostructured materials based on Zr-Al-Ni-Cu metallic glasses have been synthesized by controlling the nucleation and growth rates of the precipitated phase correlated with the unique icosahedral local structure. It is well known that the Zr65Al7.5Ni10Cu17.5 metallic glass has a high glass-forming ability (GFA), which enables us to produce the glassy sample with a bulky shape. By substitution of Pd with Cu, the primary phase changes from the metastable fcc-Zr2Ni phase into the nanoscale icosahedral quasicrystalline phase (I-phase). It is found that the nucleation frequency increases drastically with the Pd addition, which results in the formation of nanostructured materials. The nanoscale structure control in metallic glasses exhibits unique mechanical properties such as a high strength and good ductility.