Mechanoimmunology explores how mechanical forces orchestrate immune responses, offering insights into immune cell functions and the mechanisms underlying mechanotransduction. A critical challenge in this field is the absence of reliable platforms that apply precise, consistent mechanical stimuli to individual cells while enabling reproducible immune activation. Here, we present a nanoscale acoustic oscillator for mechanoimmunology applications: NAOMI. NAOMI features micropatterned pillars that support uniform cell monolayer formation with an integrated acoustic transducer that delivers highly controlled 3D nanoscale oscillations (±1-nanometer deviation) for up to 72 hours. Unlike conventional passive platforms relying on static stiffness or surface topography, NAOMI enables dynamic, programmable stimulation with high precision and reproducibility. Validation studies demonstrate that NAOMI notably enhances mechanical stress intensity and cell displacement, driving robust M1 polarization in macrophages. NAOMI provides a practical and versatile platform for studying mechanoimmunology, offering high precision, stability, and tunability. Its capabilities also position it well to support future research and drive innovative discoveries in the field.