The nutritional composition of chocolate varies according to the percentage of cacao it contains and what is added to it (milk, nuts etc). Here are the average values for 100g:
Dark chocolate with 86% cacao solids: 567 kcal, 9.7g protein, 19.1g carbohydrate, 50.2g fat and 9.3g fibre.
Dark chocolate with 70% cacao solids: 561 kcal, 8g protein, 31g carbohydrate, 45g fat and 7g fibre.
Dark chocolate with 64% cacao solids: 521 kcal, 8g protein, 39g carbohydrate, 37g fat and 4g fibre.
Milk chocolate: 567 kcal, 6.7g protein, 51g carbphydrate, 37.3g fat, 1.3g fibre.
White chocolate: 543 kcal, 8g protein, 58.3g carbohydrate, 30.9g fat, 0g fibre.
Cacao paste used for dark and milk chocolate also contains a selection of vitamins and minerals (calcium, iron, fluoride, copper, Vitamins A, B and E) and molecules (theobromine, caffeine, serotonin, tyramine and polyphenols).