Herein, a novel chitosan derivative nanoparticle was proposed to function as a delivery carrier. First of all, an improvement was made to the way N-2-hydroxypropyl trimcthyl ammonium chloride chitosan (N-2-HACC) was synthesized. Moreover, the solution to one-step synthesis of N-2-HACC from chitosan (CS) was developed. Different from the previous report, the synthesis process was simplified, and there was a reduction in the amount of 2,3-epoxypropyl trimethyl ammonium chloride (EPTAC) used. With its excellent water solubility maintained, the relatively low degree of substitution was controlled to facilitate the cross-linking reaction. The results obtained from H-NMR, FTIR spectroscopy, and XRD indicated a smooth EPTAC onto CS for the formation of N-2-HACC with 59.33% the degree of substitution (DS). According to our results, N-2-HACC could be dissolved in various organic solvents, deionized water, 1% acetic acid aqueous solution, and others at room temperature. Finally, a novel chitosan nanoparticle material was prepared using the self-assembly method with β-glycerophosphate sodium (β-GC), with excellent immune properties achieved, thus providing a new strategy for chitosan self-assembled nanoparticles.