I’m not sure if you are referring to the NATO intervention in the first part of the wars as Yugoslavia broke up (Bosnia, primarily starting in 1992) or later (t

I’m not sure if you are referring to the NATO intervention in the first part of the wars as Yugoslavia broke up (Bosnia, primarily starting in 1992) or later (the NATO-Yugoslavia war over Kosovo, starting 1999) or layer yet (the NATO involvement in the internal conflict of then-NATO partner North Macedonia in 2001), but all three were official NATO operations (and listed as such on NATO’s website.)