There is a growing effort in the scientific community to design and fabricate even more portable and efficient devices working with multivalent mixtures of electrolytes. In this context, a molecular level understanding of interfacial fluid dynamics can enable the design of ultra-miniaturized platforms with their functional stages integrated by electrically controlled nanoconduits. In nanoconfined multivalent electrolyte solutions, a counter-intuitive phenomenon known as charge inversion (CI), occurs within the electrical double layer (EDL). CI takes place as the charge density provided by the co-ions exceeds that one provided by the interfacial counter-ions in the EDL. Indeed, more than expected Co-ions move to the EDL due to the presence, near the channel wall, of an excess of highly hydrated multivalent counter-ions which enable the overscreening and charge reversal of the apparent local surface charge. Despite previous efforts, the fundamental factors governing CI and its effects on nanoconfined multivalent ionic fluid transport remain poorly comprehended. Previous studies fail to provide a comprehensive understanding of this intricate phenomena at electrically charged interfaces. Further research is needed to achieve a comprehensive understanding of nanoconfined flows of multivalent electrolytes. Here, we employ non-equilibrium all-atom Molecular Dynamics simulations to study Poiseuille-like and elecroosmotic flow in silica nanochannels of a water electrolyte solution including different concentrations of Magnesium, Sodium and Chloride. In contrast to the conventional approach of locating the z-potential at an imaginary plane near the outer Helmholtz plane, which attempts to reconcile the Poisson–Boltzmann and Navier–Stokes equations, our findings contradict the validity of this concept as it is not appropriate due to the absence of a stagnant fluid within the fluid layers adjacent to the charged surface. Hence, we suggest that the assumption that the z-potential is located at a sharp boundary between the hydrodynamically mobile and immobile fluid is misleading for describing the complex phenomena taking place within the EDL. Our study discloses how CI alters the electrokinetic phenomena, interfacial fluid structure and transport properties in nanoconfined electrolyte solutions which contribute to the development of more realistic models for describing electrokinetic phenomena.