Reese's Pieces have no chocolate in them. The peanuts had their oil pressed out and a cheaper fat put back in.
Sugar is first, then partially defatted peanuts, then hydrogenated palm kernel and soybean oil, then corn syrup solids. Everything after that is 2% or less, and it's the dyes, the glaze, some vanillin and a little milk. There's no cocoa anywhere.
Partially defatted just means the peanuts went through a press. The peanut oil comes out one side and gets sold as peanut oil. What's left is a dry peanut flour, and that's what the center is made from, because flour holds a shape in a panning drum and doesn't go rancid. Then they put fat back in, and the fat they picked is hydrogenated palm kernel oil, which is solid at room temperature and costs less than peanut oil. You can see the swap on the panel. 38 pieces have 6 g of fat and all 6 are saturated. Peanut oil is mostly unsaturated, so that number isn't the peanut.
The shell is sugar with 4 dyes and a coat of shellac.