Composite chitosan nanofibers containing 20 wt % chitin nanofibrils and 10 wt % PEO are obtained via the electrospinning method. Additions of 0.5-20.0 wt % chitin nanofibrils into chitosan solutions with concentrations of 3-7 wt % in acetic acid (70 vol %) insignificantly increase the electrical conductivity, surface-tension coefficient, and viscosity of these mixed solutions. Decreases in the viscosities of chitosan solutions containing chitin nanofibrils with increases in shear rate provide evidence for the structuring of solutions and the orientation of chitosan macromolecules and chitin nanofibrils in the shear flow. The effects of shear stress and a high-voltage electric field on chitosan solutions containing chitin nanofibrils and PEO result in a decrease in the imperfection of composite nanofibers. The introduction of chitin nanofibrils allows the content of PEO in the composite nanofibers to be reduced.