ΔE 16.1, loose: different enough that you should pick on purpose. Sick Green is a little darker, warmer than Bright Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Sick Green is a little darker, warmer than Bright Green.
The same difference applies the other way round: Bright Green is a little lighter, cooler.
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 Bright Green on the colour wheel See Sick Green on the colour wheel
All matches: Bright Green equivalents · Sick Green equivalents