Biodegradable blend nanocomposites containing 75 wt% of amorphous or crystalline polylactide (PLA) with 25 wt% poly [(butylene adipate)-co-terephthalate] (PBAT) and cellulose nanocrystals (CNCs) were separately prepared using a solvent casting method. Two solvents were used to disperse the CNCs and dissolve PLA, PBAT and their blends. The rheological behavior of the nanocomposites obtained after drying were analyzed in dynamic and transient flow fields in molten state. For both amorphous and crystalline PLAs the complex viscosity and storage modulus of nanocomposites and their blends increased markedly with CNC contents as low as 1 wt%, which is an indication of highly dispersed CNCs with a network-like behavior. The formation of an interconnected CNC network within the polymers and their blends was confirmed through stress growth experiments where the initial overshoot caused by the deformation of CNC network could be observed again after a sufficient rest time. The most remarkable result observed is the effect of traces of solvents left after drying on the complex viscosity of the neat polymers, which decreased by 1 and 2 orders of magnitude for the crystalline and amorphous PLAs, respectively, in comparison of the unprocessed granules. On the other hand, the complex viscosity of the PBAT was not changed after preparation through solvent casting. This is believed to be due to the important PBAT crystallization during drying at 70 C.