Photoshop Elements 14 first installs with Camera Raw 9.0. Your camera requires at least Camera Raw 9.121. You can update Camera Raw to 9.5. Check for updates and get Camera Raw updated, and then you should have support for your NEF files.
I think the OP will either have to convert to DNG or upgrade to Elements 2018, Jim.
As you say, the D850 was first supported in 9.12.1. Elements 14 is only compatible with Camera Raw up to 9.5 (7 dot releases behind).
Although it's not mentioned here Camera Raw plug-in and Adobe application compatibility , I think only Elements 2018 is compatible with Raw 9.12.1.
Of course! I wasn't thinking. 12 is higher than 5. I have corrected that misunderstanding myself in the past. Sorry.
No need to apologize, Jim. Adobe's version numbering is confusing at the best of times.