We investigate the thermorheological properties of a partially miscible polymer blend exhibiting lower critical solution temperature phase diagram and having high glass transition and molecular weight constituents, namely poly(styrene-co-maleic anhydride)/poly(methyl methacrylate), SMA/PMMA, in the nonlinear regime. By using parallel plate, sliding plate, and capillary rheometry, with the knowledge of the blend’s phase behavior, we address the following aspects of its dynamic response: (i) the sensitivity of nonlinear viscoelastic properties to the phase behavior, which is reflected in the observed thermorheological complexity and a dual-peak stress response in large amplitude oscillatory shear; (ii) the effects of shear history on the morphological and rheological properties, which corroborate the picture of shear-induced fibrilar-type growth of the SMA-rich inclusions in the phase separated regime; and (iii) the evolution of shear and normal stresses and the relevant morphological changes in the phase s...