An exhaust nozzle assembly for a propulsion system include a primary nozzle, an outer shroud, an ejector nozzle, and an actuator. The primary nozzle extends along an exhaust centerline. The primary nozzle includes a downstream axial end. The outer shroud surrounds the primary nozzle. The ejector nozzle extends axially between a first axial end and a second axial end. The second axial end forms a nozzle exit plane for the exhaust nozzle assembly. The ejector nozzle converges in a direction from the first axial end to the second axial end. The ejector nozzle forms a mixing cross-sectional area between the primary nozzle and the ejector nozzle at the downstream axial end. The actuator is mounted on the ejector nozzle. The actuator is configured to move the ejector nozzle between a first position and a second position, relative to the outer shroud, to control an area of the mixing cross-sectional area.