ΔE 15.2, loose: different enough that you should pick on purpose. Chestnut Brown is a little darker, much more saturated than Eshin Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Chestnut Brown is a little darker, much more saturated than Eshin Grey.
The same difference applies the other way round: Eshin Grey is a little lighter, much more muted.
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 Eshin Grey on the colour wheel See Chestnut Brown on the colour wheel
All matches: Eshin Grey equivalents · Chestnut Brown equivalents