ΔE 32.9, loose: different enough that you should pick on purpose. Nebula Copper is a little lighter, much more saturated, cooler than Sycorax Bronze.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Nebula Copper is a little lighter, much more saturated, cooler than Sycorax Bronze.
The same difference applies the other way round: Sycorax Bronze is a little darker, 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 Sycorax Bronze on the colour wheel See Nebula Copper on the colour wheel
All matches: Sycorax Bronze equivalents · Nebula Copper equivalents