Foam injection molding with a core-back tool allows control of the pressure release rate by adjusting the rate of displacement of a mold wall after filling and packing the base mold cavity. This process has the potential for preventing premature expansion and collapse of the foam as reported from work with physical blowing agents such as nitrogen and carbon dioxide. In particular, an appropriate choice of packing pressure and duration were shown to redissolve cell nuclei before mold opening so that greater cell density may be obtained upon mold opening or core-back displacement-- Shaayegan et al., (2017). The objective of this work was to investigate the effect of molding conditions when using chemical foaming agents on the shrinkage variation along the flow length and cell structure of injection molded foam from talc-filled TPO, with and without nanoclay additives. A core-back plaque mold (420 mm x 150 mm) with a relatively long flow distance from the gate was used for foam injection molding from talc-filled thermoplastic olefin blends (TPO) with two different chemical foaming agents; the core-back displacement was along the thickness direction from 1.75 mm to 2.75 mm. The core-back displacement rate was varied from 25 mm/s to 330 mm/s. High pressure foam injection molding in the core-back plaque tool was carried out at the International Automotive Components (IAC) facility in Troy, MI. Two compounds incorporating nanoclay additives with coupling agents and polymeric modifier in the TPO were prepared in this work. Uniform thickness and shrinkage was obtained above a threshold value of pack pressure depending on the foaming agent and the compound rheology. The foam structure was also more sensitive to the mold opening rate for the nanocomposite compounds.