ΔE 17.7, loose: different enough that you should pick on purpose. Night Lords Blue is noticeably lighter, much more saturated, cooler than Ocean Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Night Lords Blue is noticeably lighter, much more saturated, cooler than Ocean Blue.
The same difference applies the other way round: Ocean Blue is noticeably 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 Ocean Blue on the colour wheel See Night Lords Blue on the colour wheel
All matches: Ocean Blue equivalents · Night Lords Blue equivalents