ΔE 23.2, loose: different enough that you should pick on purpose. Asheth Grey is noticeably darker, much more muted than Nocturne Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Asheth Grey is noticeably darker, much more muted than Nocturne Green.
The same difference applies the other way round: Nocturne Green is noticeably lighter, much more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Nocturne Green on the colour wheel See Asheth Grey on the colour wheel
All matches: Nocturne Green equivalents · Asheth Grey equivalents