Thai khao mok is built lighter than the briyani it descends from. The rice is cooked with turmeric, a spoon of ghee or butter and stock, then steamed, so 220g of it is about 330 calories against 400 or more for oily Indian style rice. The chicken is one bone in thigh, about 130g raw, cooked in the rice, so it does not get fried. That thigh with skin is about 190 calories and 20g of protein.
The green sauce (nam jim khao mok) is sugar, vinegar, green chili, mint and coriander blended. A small dish is about 25g and 20 calories, almost all sugar. The fried shallots on top are 5g and 20 calories. And the bowl of clear soup on the side is about 15 calories and worth drinking. None of these move the plate much; the rice is two thirds of the total.
Portions vary more than most Thai plates. A stall that serves a small thigh and a modest scoop of rice is around 420. A restaurant plate with a big leg quarter and a heaped rice mound is 680 or more. Khao mok nuea (beef) is a bit higher because the beef is braised in fat, and khao mok pae (goat) higher still at around 620 for the standard plate.