This study investigated the influence of carbon nanotubes (1-5 wt.%) into 30 wt% cBN (Ni coated)-Al2O3 composite. Hybrid nanocomposites were prepared via spark plasma sintering (SPS) at 1400 degrees C to target the optimum properties and innovative solutions to self-lubricating ceramic cutting inserts. The hybrid nanocomposite prepared with the lowest reinforcement (1 wt.% CNTs) showed the highest thermomechanical and tribological properties due to the better distribution of CNTs and interfacial bonding provided by the nickel coating on hard cBN particles, leading to better densification. The wear rate and coefficient of friction (COF) reduction are attributed to the self-lubrication provided by a small quantity of hBN, Ni, and CNTs in the alumina matrix. The 1 wt.% composition shows a high hardness value (H-n approximate to 25.5 GPa) and high thermal conductivity (approximate to 31.9 W/m & sdot;K) with a coefficient of thermal expansion (CTE) of approximate to 6.1 ppm & sdot;K-1. However, incorporating a higher CNT content reduced grain growth, interfacial bonding strength, and phase transformation from the more challenging phase (cBN) to the softer phase (hBN). Interestingly, the COF was significantly reduced to similar to 0.28 with increased CNTs (wt.%). Furthermore, the increased CNT content significantly enhanced the elastic modulus (E-r approximate to 617 GPa). It yielded an ultralow CTE (approximate to 4.4 ppm & sdot;K-1), which can be attributed to the densification and inherent nature of CNTs. This comprehensive analysis offers invaluable insights into the design and optimisation of hybrid composite materials for environment-friendly machining applications. Hybrid compositions were designed for hard-to-machine materials (i.e., titanium, superalloys) under dry conditions to be environmentally friendly and economically viable.