The hydraulic performance for non-Newtonian nanofluid for two-dimensional, steady, laminar flow through a channel with a backward-facing step is numerically investigated. The different nanoparticles (i.e., Ag, diamond, Au, Al2O3, TiO2, SiO2, CuO, and Cu) are spread in a pure base fluid (CMC/water with 0.3%). The channel step height and the expansion ratio for the backward-facing step are considered as 4.8 mm and 2, respectively, and simulations have been performed for a Reynolds number (Re) range (50 ≤ Re ≤ 175). A primary recirculatory zone is generated and begins to transit into a fully developed flow. It is observed that the length of reattachment shifted toward downstream, away from the vertical step as we increase Re. It is revealed that among the different types of non-Newtonian nanofluid, SiO2 nanoparticles have the maximum velocity among other nanoparticles, and Au nanoparticle has the smallest value of velocity. The wall shear stress and static pressure increase as Re increases, and the skin friction coefficient decreases significantly.