We report on the first experimental demonstration of vibrating two-dimensional nanoelectromechanical systems (2D NEMS) with on-chip piezoelectric excitation. Combining a wafer-scale aluminum nitride (AlN) thin film technology with an all-dry transfer technique for atomic layer 2D semiconductors, we fabricate and piezoelectrically excite few-atomic-layer molybdenum disulfide (MoS2) NEMS resonators in the high frequency (HF) band. Multimode resonances up to 38MHz are observed, with efficient electromechanical drive from the AlN layer off the vibrating 2D NEMS device region (to avoid compromising the movable 2D device by electrodes needed for on-chip excitation and readout). The piezoelectrically excited 2D NEMS resonators may enable remotely driven, ultrasensitive transducers. Combined with on-chip electrical readout techniques (e.g., mixing), this device platform also holds promise for future radio frequency (RF) electronics and integrated systems.