The new ON1 Photo RAW 2019 is now officially released and has support for the latest Nikon cameras including the D850 and Z7 (the press release can be found here):
Screenshots:
Full list of supported Nikon cameras:
Nikon 1 AW1
Nikon 1 J3
Nikon 1 J4
Nikon 1 J5
Nikon 1 V3
Nikon COOLPIX A
Nikon COOLPIX P330
Nikon COOLPIX P340
Nikon COOLPIX P6000
Nikon COOLPIX P7100
Nikon COOLPIX P7700
Nikon COOLPIX P7800
Nikon D100
Nikon D200
Nikon D2X
Nikon D3
Nikon D300
Nikon D3000
Nikon D300S
Nikon D3100
Nikon D3200
Nikon D3300
Nikon D3400
Nikon D3S
Nikon D3X
Nikon D4
Nikon D40
Nikon D4S
Nikon D5
Nikon D50
Nikon D500
Nikon D5000
Nikon D5100
Nikon D5200
Nikon D5300
Nikon D5500
Nikon D5600
Nikon D60
Nikon D600
Nikon D610
Nikon D70
Nikon D700
Nikon D7000
Nikon D70s
Nikon D7100
Nikon D7200
Nikon D750
Nikon D7500
Nikon D80
Nikon D800
Nikon D800E
Nikon D810
Nikon D850
Nikon D90
Nikon Df
Nikon E5400