This study investigates the heat and mass transfer rates in an MHD viscoelastic nanofluid flow, specifically employing Walter's liquid-B model. The flow occurs over a stretching sheet subjected to heat generation/absorption and thermal radiation. The mathematical framework adheres to the fundamental principles of motion and heat transfer. By employing similarity transformations, the governing equations are transformed into a set of nonlinear ordinary differential equations (ODEs). Utilizing the Homotopy Analysis Method (HAM), we obtain numerical solutions for these nonlinear ODEs and their associated boundary conditions. Graphical analysis is conducted to examine the behavior of the resultant equations under the influence of various flow parameters. It is observed that the heat transfer rate diminishes with an increase in the Brownian motion parameter, while it improves with an increase in the thermophoresis parameter. Higher values of the viscoelastic and stretching parameters lead to accelerated velocity slip. The viscoelastic nature of the nanofluid results in reduced values for local skin friction, Nusselt, and Sherwood numbers. Notably, the slip parameter has a significant impact on flow velocity.