Nitro-oxidized carboxylated cellulose nanofibrils (NOCNFs) from the banana rachis are employed in oil-emulsion coolant as an additive. The concentrations of NOCNF were 0.1, 0.2, 0.3 wt. %. The cutting parameters include the spindle speeds and depth of cut. The temperature and wear reduction were significant. The temperature at the tool flank decreased from 119°C to 76°C, corresponding to an 11% reduction in wear at the depth of cut co. 2 mm and spindle speed of 1330 rpm. The viscosity of the nanofluid and the corrosion of the low-carbon mild steel specimen are discussed. Arguably, a stable NOCNF nanofluid suspension is good against wear even at elevated temperatures. Interestingly, these results occurred at a lower NOCNF concentration co. 0.3% wt. compared to 1–2 wt. % from Al2O3 nanoparticles in literature. In this paper, banana rachis nanofibrils are attractive for developing of effective and environmentally friendly additives from biomass.