(AC), a medicinal fungus native to Taiwan, contains bioactive compounds such as triterpenoids with anticancer properties. However, their high lipophilicity results in poor aqueous solubility and limited bioavailability, restricting their therapeutic application. To address this issue, a nanoparticle-based delivery system was developed using chitosan, alginate, and hyaluronic acid to encapsulate AC extracts. AC-loaded nanoparticles (AC-NPs) with a particle size less than 100 nm improved drug solubility and facilitated intracellular accumulation. Assessment of cytotoxicity revealed that AC-NPs significantly and more effectively suppressed the growth of breast cancer cells than free AC extracts. After 72 h, IC values for MDA-MB-231 (triple-negative) and MCF-7 (estrogen receptor-positive) were 46.9 and 75.6 μg/mL, respectively, with greater sensitivity observed in MDA-MB-231 cells. AC-NPs exhibited minimal toxicity toward normal mammary epithelial cells (NMuMG), indicating good biocompatibility. Fluorescently labeled AC-NPs showed rapid, time-dependent uptake in both cancer cell lines. Particularly, MDA-MB-231 cells exhibited rapid internalization, whereas MCF-7 cells likely benefited from hyaluronic acid-mediated targeting of CD44 receptors. In conclusion, AC-NPs enhanced the solubility, cellular uptake, and anticancer efficacy of AC while maintaining biocompatibility, thereby suggesting their robust potential as nanocarrier platforms for breast cancer therapy.