To investigate the influence of molecular weight on the production of chitin nanofibers, we used chitin of different molecular weights to produce nanofibers under identical chemical bleaching, high-speed shearing, and ultrasonication conditions. The yield and morphological characteristics of nanofibers produced under the same preparation conditions using chitin with different molecular weights were examined. Because low-molecular-weight chitin (SSHC) yields shorter fiber lengths and fewer entanglement points, SSHC facilitates fibrillation, resulting in a higher nanofiber yield. Processing does not alter the chemical structure and crystalline phase of SSHC, enabling efficient production of chitin nanofibers with diameters ranging from 50 to 125 nm with relatively short ultrasonication times (30 min), ultimately achieving yields of up to 32.07%. This research reveals the benefits of using low-molecular-weight chitin for nanofiber fabrication and highlights their promise as stabilizers in Pickering emulsion systems. These finding provide strong technical support for value added chitin utilization.