ΔE 19.0, loose: different enough that you should pick on purpose. Midnight Ink is noticeably darker, more muted, warmer than Triumphant Navy. They are different kinds of paint: Army Painter Triumphant Navy is an opaque base/layer paint and Nocturna Models Midnight Ink is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Midnight Ink is noticeably darker, more muted, warmer than Triumphant Navy. They are different kinds of paint.
The same difference applies the other way round: Triumphant Navy is noticeably lighter, more saturated, 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 Triumphant Navy on the colour wheel See Midnight Ink on the colour wheel
All matches: Triumphant Navy equivalents · Midnight Ink equivalents