I noticed this expression in the newspaper and had to investigate what it was. It is a shoe. In this context, chocolate is the color of chocolate, crocodile is the skin of the animal used as a material, and kitten heels is a style of shoe, with a petite heel; petite is a salient attribute of kittens and the heel is metonymic for the whole shoe. To the extent that I have a feel for this, a shoe wouldn’t necessarily be referred to as a kitten heel if the rest of the shoe didn’t also have the attributes characteristic of this kind of shoe, for example a boot with kitten heels might be referred to as a kitten heel boot.

The example shows how four nouns in a row conceal an intricate underlying structure; given these cultural associations, you wouldn’t call the same thing a crocodile chocolate kitten heel, and certainly not a chocolate kitten crocodile heel. The color has to come before the material, and “kitten heel” can’t be broken up.

Color comes before material systematically, for example in blue suede shoes, yellow rubber ducky, and red silk pajamas.

Normally, shape can precede material: square wooden table, flat plastic disk, long steel knife. Kitten heel can’t be separated, though, because the two parts have a conventionalized meaning togther; they form a kind of a compound.