Eosinophils drive anti-tumor immunity via cytotoxic T-cell recruitment, yet their utility is limited by the chromatin-bound nuclear sequestration of IL-33. We developed "NanoBurst", an ultrasound-activated, PFH-encapsulated polymeric nanobubble designed to disrupt plasma and nuclear membranes via acoustic cavitation. Ultrasound-induced PFH vaporization generates mechanical stress, releasing intact nuclear DAMPs (IL-33, HMGB1, GSDME) without denaturation. Released IL-33 triggers an eosinophil cascade, increasing NK and CD8+ T-cell infiltration into the tumor microenvironment. Combined with Sitagliptin (DPP4 inhibitor), NanoBurst significantly inhibited CT26 primary tumors and lung metastasis, surpassing anti-PD-1 efficacy. This platform precisely mobilizes sequestered DAMPs to harness eosinophil-driven immunity, offering a potent alternative for immune checkpoint inhibitor-refractory cancers.