The invention provides an improved nozzle assembly for waterjet-propelled watercraft such as a personal watercraft. In particular, the invention features an improved reverse gate assembly used to travel in a reverse direction. The reverse gate is linked to the steering-controlling waterjet outlet nozzle and pivots laterally with it to provide significantly enhanced steering response and control when the reverse gate is extended for reverse direction travel of the watercraft. The reverse gate actuation linkage assembly enables such linkage of the reverse gate and the steering-control nozzle member even when the nozzle is configured to pivot vertically (in addition to laterally) to “trim” the attitude of the watercraft in the water. Differential or laterally asymmetric design of the reverse gate compensates for vorticity or swirl in the waterjet to help ensure uniform watercraft performance when travelling in a reverse direction and turning either to the right or to the left.