Procedures may vary, but at first sign of an engine failure it is nose down.
That would depend at which stage of flight you are in.
And yes the Boeing/Airbus video on stalls is very informative but that relates to "big" under the wing jet powered aircrafts and may not necessarily apply for a turboprop type aircraft.
Although speculative at this time on my part and as others have also speculated, it could be that a VMCA incident occurred.
Time will tell when the "black boxes" are read.