There are two types of Kinder Eggs: Kinder Surprise[1] and Kinder Joy[2]. Kinder Surprise is banned in the US because it contains "non-nutritive objects" inside the egg. Kinder Joy packs the toy separately and has been sold in the US since 2017.
I bought one the other day. It turns out the US kinder egg is nothing like the EU one. The EU one is a chocolate shell containing a plastic package with a toy in it. the US one is two halves, one with a toy, and the other containing a (white-chocoate?) fondant with 2 hazelnut-chocolate balls in it. It was pretty bad and I threw it out after trying it.
My apologies, where I come from, the UK, Kinder Egg is colloquially used in place of Kinder Surprise. It wasn't until a week ago, after decades of only knowing one type of Kinder Egg, that I came across Kinder Joy.
I've just seen on the Kinder Surprise Wikipedia page.. https://en.m.wikipedia.org/wiki/Kinder_Surprise the very first line "Kinder Surprise, also known as Kinder Egg"