ΔE 14.4, fair: the same colour family, but not a straight swap. Warp Lightning is a little darker, more saturated, cooler than Matt Light Green. They are different kinds of paint: AMMO by Mig Matt Light Green is an ink, glaze or transparent paint and Citadel Warp Lightning is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Warp Lightning is a little darker, more saturated, cooler than Matt Light Green. They are different kinds of paint.
The same difference applies the other way round: Matt Light Green is a little lighter, 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 Matt Light Green on the colour wheel See Warp Lightning on the colour wheel
All matches: Matt Light Green equivalents · Warp Lightning equivalents