ΔE 30.3, loose: different enough that you should pick on purpose. Yellow Green is much more saturated, cooler than Valkyrie Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Yellow Green is much more saturated, cooler than Valkyrie Yellow.
The same difference applies the other way round: Valkyrie Yellow is much 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 Valkyrie Yellow on the colour wheel See Yellow Green on the colour wheel
All matches: Valkyrie Yellow equivalents · Yellow Green equivalents