Hmm, had a look at the file and it looks like the combination of multiple files. I did see (part of) an XMP metadata block, but I also saw references to Cryptographic algorithms (AES, SHA256, etc.), but also to printers/scanners, audio, (error) messages (indicating application code is intermingled as well), etc. So basically the file is a complete mess of data from all sorts of places on your disk.
With Phil's extract_preview (search on the the forum and it should pop up), I was able to extract 11 (!) images, but only 2 of them contained a viewable image, the other ones looked more like icons or where completely corrupt. But since they are both only 1200x800 in size it is very unlikely the are from your NEF. The images that where more likely to be from a NEF (though still not the 600x4000 I'd expect from a D7200) were completely destroyed (i.e., mostly just grey) so nothing useful there.
Hopefully you still have the original files on the SD, otherwise I'm afraid retrieving anything useful is a lost cause
I've attached the two images I recovered so you can see if they could be from the shots you lost.
Fore reference, this is the complete output of extract_preview -a DSC_1232.NEF
[extract_preview version 1.03]
Found JPEG (6x6 pixels, 21843 bytes at offset 5612499)
Found JPEG (256x192 pixels, 15095 bytes at offset 5634395)
Found JPEG (64x48 pixels, 3312 bytes at offset 5649551)
Found JPEG (64x48 pixels, 3028 bytes at offset 5652933)
Found JPEG (4500x3000 pixels, 341613 bytes at offset 6434816)
Found JPEG (4500x3000 pixels, 217444 bytes at offset 7745536)
Found JPEG (4170x3000 pixels, 377233 bytes at offset 8073216)
Found JPEG (4500x3000 pixels, 333627 bytes at offset 8892416)
Found JPEG (1200x800 pixels, 246296 bytes at offset 11821056)
Found JPEG (80x80 pixels, 1323 bytes at offset 22892544)
Found JPEG (1200x800 pixels, 166997 bytes at offset 26046464)
--> saved 11 previews
1 files processed
11 previews created: