Hi James.
When viewing a RAW file most image viewers simply reflect the JPG that’s embedded within it, and the camera’s preview mode is doing the same.
Yes, that’s PhotoLab applying its RAW processing logic.
The result you’re then seeing is the rendered image after PL has applied its RAW processing logic to the RAW file.
The fact that this result is different to the embedded JPG rendition may be due to a “Picture Profile” or “Creative Effect” that you perhaps have assigned in your camera set-up - (Those being Sony terms for what I’m assuming are also available for your Nikon camera) - as these will affect the JPG but not the RAW/NEF file.
HTH - John M
Edit: James - There’s a similar reference to your observation here.