Hi, Sam -
Thanks for answering. In fact, there is a way to set the Bayer matrix in Nebulosity 4. Under the "Image" menu, "De-mosaic RAW..." gives you a "Manual Demosaic Setup" dialog box in which you can set both the matrix values and the offset (X,Y = 0 or 1).
For what it's worth, I found a matrix for the IMX071 chip in a review of the Nikon D7000 on dxomark.com (https://www.dxomark.com/Cameras/Nikon/D7000---Measurements).
The reason I went through the exercise in the first place is that the automatic debayering in Nebulosity gave me a blue and purple M42! It's very pretty, but it's not what people expect to see
Best regards,
Bill Arden