A bio-based rigid polyurethane (PU) nanocomposite foam was synthesized by reacting palm kernel oil polyol with 4, 4-polydiphenylmethane diisocyanate (p-MDI) at 1:1 NCO: OH ratio via direct mixing method. Nanofiller halloysite nanotube (HNT) was added at three different loadings i.e. 1 wt%, 3 wt% and 5 wt%. Thermal stabilities and morphologies of nanocomposite were investigated. Fourier Transform Infrared (FTIR) analysis confirmed the formation of polyurethane with detection of wavebands at 1,714 cm-1, 1,518 cm-1 and 1,209 cm-1, corresponding to urethane linkages. Scanning electron microscopy (SEM) images displayed bigger cells sizes and smooth cells surfaces, owing to abilities of HNTs to form two nucleating sites and reduced the interfacial tension between the cells. Results from thermogravimetric analysis (TGA) showed good improvements on the thermal stabilities on the foams. In contrast, the flammabilities of the foams did not show significant changes with the addition of HNTs in the systems.