When the filler content is higher than a critical threshold, flocculation of naoparticles in polymer melts, eventually results in three dimensional networks Of clusters. The marked elastic feature of such structures combines with that of the polymer melt giving rise to a complex dependence of the linear viscoelastic moduli on frequency and filler content, We analyze a wide variety of polymer nanocomposite systems and show that a unifying description of their viscoelasticity is Possible irrespective of the nature of pristine nanoparticles and the degree of polymer-filler affinity. We validate our approach through the building of master curves of the elastic modulus of samples at different composition. Possible general trends in the stress bearing mechanisms of the different kinds of network considered are also discussed. Given its generality, the proposed analysis is expected to be useful to describe a wide variety of complex fluids in which a superposition of the elasticity of the components is possible.