I'm basing my suggestion on the Gazelle in which I have done OGE hovering and throttle chops but also the Sea King where we trained for forced landing from an OGE hover when we started a lot of FLIR searching.
In both cases, initiating with rapid down collective produced a nose down pitching and a reduction in g.
If this doesn't happen in Robinson aircraft then I'm surprised but happy to have my knowledge improved - not that I'll ever get in one of them again!
If you slam the collective down fast in an R22/R44 you will get a brief moment of negative G's,...and I mean brief, its barely one second.
However, I cannot think for the life of me why anyone would chop the throttle in a HOGE in a Robby. In all the years I was subjected to throttle chops never once was it done in a HOGE. Zero airspeed autos like that were always initiated with a smooth lowering of the collective followed by a slow rolling off of the throttle.