Yes and No. Like all culture-specific words, there are rules.
Nappy means kinky hair. Add it to the list of words you can’t say unless you are of Afro descent. And even if you do, Black, yellow, brown or white — another of Afro descent may still check you for it.
You don’t remember the big controversy over the old sports commentator calling the WNBA player a “nappy headed ho”? That was racist.
That said, yes most all understand that a nappy is a diaper.
Context matters.
Maybe you can share that perspective.
Keep the screename if you want, but you may want to prepare for assumptions that are sure to be tossed your way.
Signed,
One of Afro descent