ΔE 12.5, fair: the same colour family, but not a straight swap. Death Korps Drab is noticeably lighter than Tainted Garden.
Can I use Death Korps Drab instead of Tainted Garden?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Death Korps Drab is noticeably lighter than Tainted Garden.
Can I use Tainted Garden instead of Death Korps Drab?
The same difference applies the other way round: Tainted Garden is noticeably darker.
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.