Background <p>Nonlinear Energy Sinks (NESs) have been successfully deployed to control hazardous stall-induced aeroelastic responses.</p> Purpose <p>This study investigates the effectiveness of NES, its parameters and location on airfoil for optimal suppression of stall flutter oscillations.</p> Methods <p>A mathematical model encompassing a pitch-plunge airfoil is considered. A NES is attached to the chord of the airfoil. Through succinct numerical simulations, we demonstrate the role of NES in possibly reducing the oscillatory instabilities that arise due to a dynamic stall behaviour.</p> Results <p>We show that amplitude reductions of 30% are possible upon suitably tuning the NES in both deterministic and stochastic flow cases. Heuristically extending the scope of study to multi-NES resulted in minimal improvement in the suppression of oscillatory instabilities.</p> Conclusion <p>This is possibly the first study to successfully demonstrate amplitude reductions in stall-induced aeroelastic instabilities using NESs. We believe that the findings presented in this study may augment safer operating conditions for aeroelastic systems fraught with dynamic stall-driven instabilities.</p>