Maybe a correction would be to use the mixture of coconut milk powder and powdered sugar on the first rolling, but just powdered sugar on the second. (kingarthurflour.com)
But you are on the right track — for milk chocolate, you will just need to add milk powder (I use coconut milk powder for vegan chocolate). (nutritionrefined.com)
Our organic coconut milk powder adds the perfect creamy consistency for extra indulgence that can be enjoyed by anyone, anytime. (us.foursigmatic.com)