The present paper investigates the effect of suspended particles on thermal convection in rotating Casson nanofluids saturating a Darcy-Brinkman porous medium which has various applications in different sectors, including those that process food, paint, water generators, electricity generators, hydrology, and geophysics, heavily rely on rotation in thermal convection. With the aid of the Galerkin 1st approximation technique, the numerical examination is carried out. The Darcy-Brinkman porous media and particles suspension are taken into consideration throughout the conduct of this study. The non-Newtonian Casson nanofluid, Darcy-Brinkman porous medium, particle suspension and rotation parameter, and their impact on thermal convection have been analyzed and presented graphically for free-free, rigid-rigid, and rigid-free boundaries. It is found that for all boundary conditions the Casson nanofluid and suspended particle parameters have destabilizing impact on the stationary convection, whereas the parameter which occurred due to presence of rotation, i.e., Taylor number and Brinkman porous medium parameters, both delayed the stationary convection. In addition, we have discovered that for realistic rigid-rigid boundary condition, the system is determined to be more stable than for the other two boundary conditions. Also, on the basis of several approximations on the Taylor number and other parameters, the critical wave number and value for stationary convection are determined.