The paper studies the high-temperature structure of a chaotic potential (CP) induced in heterojunctions of the group III nitrides by the electrostatic field of charged dislocations. The CP amplitude in the junction plane has been obtained taking into account the spatial dispersion of a dielectric response of two-dimensional electron gas. The dependence of the CP properties on the parameters of the system was found. In particular, the magnitude of the CP amplitude exceeds that of the thermal energy, if the two-dimensional non-degenerate gas given in III-nitride heterojunctions and the dislocation densities being up to and over 1010 cm–2.