Firstly you will need to download and apply the denissoliveira variant pack mod https://www.digitalcombatsimulator.com/en/files/3339262/
Then I highly recommend this mod is applied with a mod applying tool like OVGME, otherwise it defeats the objective of being able to quickly apply the different nose colours to match varying skins.
The Mod contains 5 nose mods, individually coloured to match existing British variant skins available in the downloads section, (I take absolutely no credit for these brilliant skins made by our DCS community).