ΔE 16.3, loose: different enough that you should pick on purpose. Thousand Sons Blue is much more saturated, warmer than Night Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Thousand Sons Blue is much more saturated, warmer than Night Blue.
The same difference applies the other way round: Night Blue is much more muted, 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 Night Blue on the colour wheel See Thousand Sons Blue on the colour wheel
All matches: Night Blue equivalents · Thousand Sons Blue equivalents