Magnesium-ion batteries (MIBs) and dual-salt magnesium/lithium-ion batteries (MLIBs) have emerged as promising contenders for next-generation energy storage. In contrast to lithium metal anode in lithium metal batteries, magnesium metal anode in MIBs and MLIBs presents a safer alternative due to the limited dendrite growth and higher volumetric capacity, along with higher natural abundance. This study explores a MLIB configuration with a novel cathode design by employing a 2D/2D nanocomposite of 1T/2H mixed phase MoS₂ and delaminated Ti₃C₂T_x MXene (1T/2H-MoS₂@MXene) to address challenges associated with slow kinetics of magnesium ions during cathode interactions. This cathode design takes advantage of the high electrical conductivity of Ti₃C₂T_x MXene and the expanded interlayer spacing with enhanced conductivity of the 1T metallic phase in 1T/2H mixed phase MoS₂. Through a designed synthesis method, the resulting nanocomposite cathode maintains structural integrity, enabling the stable and reversible storage of dual Mg²⁺ and Li⁺ ions. The nanocomposite cathode demonstrates superior performance in MLIBs compared to individual components (253 mAh g^-1 at 50 mA g^-1, and 36% of capacity retention at 1,000 mA g^-1), showcasing short ion transport paths and fast ion storage kinetics. This work represents a significant advancement in cathode material design for cost-effective and safe MLIBs.