ΔE 13.2, fair: the same colour family, but not a straight swap. Nurgling Green is a little lighter, more saturated, cooler than British Light Mud.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Nurgling Green is a little lighter, more saturated, cooler than British Light Mud.
The same difference applies the other way round: British Light Mud is a little darker, more muted, warmer.
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 British Light Mud on the colour wheel See Nurgling Green on the colour wheel
All matches: British Light Mud equivalents · Nurgling Green equivalents