Principal difference in origin of high-order optical non-linearities caused by metallic nanoparticles such as Cu, Ag and Au embedded destructively in oxide- and chalcogenide-type glassy matrices has been analyzed from the viewpoint of semiempirical chemical bond approach. The numerical criterion has been introduced to describe this difference in terms of mean molar bond energies character for chemical interaction between unfettered components of destructed host glassy matrix and embedded guest atoms. It has been shown that "soft" covalent-bonded networks of chalcogenide glasses of As/Ge - S/Se systems differ essentially from glass-forming oxides like silica by impossibility to accommodate agglomerates of metallic nanoparticles. In contrast, such nanostructurized entities can be well stabilized in Cu-, Ag- or Au- embedded oxide glasses in full accordance with numerous experimental evidences. Recent unsubstantiated speculations trying to ascribe this ability to fully-saturated covalent matrices of chalcogenide glasses like As2S3 are analyzed and criticized as the misleading and inconclusive ones.