A:Answer If you mean the 15" model that comes with a big proprietary brick power adapter, yes. I have the late 2019 15" Spectre x360 with 4k HDR screen and use this for my primary charger at home and on the go. It even works through a hub if the hub can handle 90W.
The 13" model comes with a 60W USB-C charger already, but this will work for that model as a replacement as well. It will adapt its output to the power demand without blowing anything up.
I've even used it to directly charge my smart phone. Obviously that doesn't use 90W.