In this communication, we consider the problem of designing robust adaptive beamformer in the newly proposed nested array, where we maintain distortionless response towards the true desired signal and suppress more interferences than the number of actual physical sensors. The essence of our proposed method is to reconstruct the interference-plus-noise covariance matrix and estimate the true desired signal steering vector. The reconstruction process is performed by projecting the spatially smoothed matrix into interference subspace. The estimation process is performed by solving an optimization problem based on minimizing the beamformer sensitivity and enforcing the estimate not to converge to any of the interference steering vectors. We also show that the constructed optimization problem can be efficiently computed at a comparable cost with that of the standard Capon beamformer (SCB). The effectiveness of the proposed method is verified through numerical simulations. A robust adaptive beamforming method applied in nested array is proposed.The interference-plus-noise covariance matrix is efficiently reconstructed.The true desired signal steering vector is precisely estimated.The corresponding beamformer weight vector can be computed with a low complexity.