ΔE 9.6, close: similar, with a visible difference side by side. Fluorescent Orange is more saturated than Nazdreg Yellow. They are different kinds of paint: Citadel Nazdreg Yellow is a one-coat contrast-style paint and Tamiya Fluorescent Orange is a fluorescent or effect paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Fluorescent Orange is more saturated than Nazdreg Yellow. They are different kinds of paint.
The same difference applies the other way round: Nazdreg Yellow is more muted.
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 Nazdreg Yellow on the colour wheel See Fluorescent Orange on the colour wheel
All matches: Nazdreg Yellow equivalents · Fluorescent Orange equivalents