Using the lattice Boltzmann technique, the mixed convection of nanofluid inside an inclined trapezoidal cavity in the presence of a multidirectional magnetic field is investigated. The sides of the trapezoidal hollow are adiabatic, with the upper moveable wall being cold and the lower wall being sinusoidally heated. In simulations, the temperature and flow distribution functions are utilized to determine all parameters related to the temperature and flow fields. On the hot wall, the effects of various Rayleigh numbers (Ra = 103, 104, and 105), inclined cavity angles (θ= 0°-90°), volume fractions of nanoparticles (ϕ== 0-3 percent), magnetic field intensity (Ha = 0-100), and applied magnetic field angle (= 0°-90°) were studied. According to the research, raising the Rayleigh number enhances heat transfer. Moreover, when all other parameters are held equal, raising the nanoparticle volume fraction enhances the average Nusselt number. Increasing the Hartmann number reduces the flow velocity inside the cavity, hence reducing heat transmission. Changes in the cavity's slope and the angle of the applied magnetic field have an effect on the flow and heat transfer as well. Manuscript profile