Why isn’t there a chicken nugget emoji?

Apple does not create them so you will need to ask the place that does:

https://home.unicode.org/

Do we really need one? What would it look like so it wouldn't be confused for a rock, or lump of dirt?

Only the Unicode Consortium decides what emojis get added. So far, no one appears to have submitted a request for such a thing:

https://unicode.org/emoji/emoji-requests.html

aidanfromrehoboth wrote:

Why isn’t there a chicken nugget emoji?

Because we have the perfectly good words "chicken nugget".