Using a 2D model of capacitively coupled Josephson junction arrays (created by a network of twin boundary dislocations with strain fields acting as an insulating barrier between hole-rich domains in underdoped crystals), we study the influence of chemical pressure (∇µ) on nonlinear (i.e., ∇T -dependent) thermal conductivity (NLTC) of an intrinsically granular superconductor.Quite a substantial enhancement of NLTC is predicted when intrinsic chemoelectric field E µ ∝ ∇µ closely matches the externally produced thermoelectric field E T ∝ ∇T . The estimates of the model parameters suggest a realistic possibility to experimentally monitor this effect in non-stoichiometric high-T C superconductors. background. In particular, it was found that at low levels of hole doping (δ < 0.2), the