In this paper, we employ all-atom molecular dynamics (MD) simulations to study the electroosmotic transport in nanochannels grafted with polyelectrolyte (PE) brushes. The paper reveals three key findings: (1) there is overscreening (OS) within the PE brush layer in presence of added salt (i.e., there are more number of screening counterions than needed to screen the PE brush charge), (2) OS ensures that there is an excess of coions within the brush-free bulk causing a coin-dictated electroosmotic transport in brush-grafted nanochannels for weak and intermediate electric field strengths, and (3) for larger electric field, OS disappears and one observes a countering-dictated EOS transport (i.e., there is an electric-field-driven flow reversal). This is Turash’s 5th, Harnoor’s 24th, and Parth’s 14th paper from the group. Congratulations All