In this study, the effects of innovative and environmentally friendly cooling-lubrication techniques on the machinability properties of CPOH cold-work tool steel were comprehensively investigated. The main objective of the research was to determine the contribution of nanofluid-based cutting fluids to machining performance and to propose new solutions that can serve as alternatives to traditional methods for sustainable manufacturing practices. Experimental studies were conducted on a CNC milling machine using an Al-TiN coated carbide milling cutter. Two different cutting speeds (100 and 130 m/min), two different feed rates (0.08 and 0.1 mm/rev), and a constant depth of cut (0.7 mm) were applied in the experiments. The nanofluids used in the study were prepared by adding certain proportions of SiO₂ nanoparticles to the synthetic cutting oil used as the base. To compare the effects of different nanoparticle ratios on machining performance, nanofluids were evaluated at 0.1 wt% and 0.2 wt% ratios. Key performance criteria such as surface roughness (Ra), cutting temperature (Tc), tool wear (Vb), and power consumption were analyzed to evaluate machinability. The findings indicate that the use of nanofluids significantly improves machining performance. In particular, the 0.2 wt% SiO₂ added nanofluid resulted in lower surface roughness and cutting temperature values, resulting in less tool wear, while also minimizing power consumption. It was determined that nanofluids with SiO₂ nanoparticles offer significant advantages in terms of thermal control, tool life, and surface quality in the milling of cold-work tool steels, and represent a strong alternative to conventional cutting fluids in terms of energy efficiency and environmental sustainability. These findings significantly contribute to the development of sustainable manufacturing technologies.