Jollibee does not put a full nutrition table on its Philippine site, but per-piece figures from their US listings are on FatSecret: thigh 380, breast 320, drumstick 220, spicy drumstick 200. The piece you get is random, so 300 is a fair average. The skin and coating are about half of that. A skinless piece of the same chicken would be around 170, but nobody buys Chickenjoy to peel it.
The rice is a full cup at about 260 calories, and the gravy tub is around 40, mostly flour and chicken fat. So the meal is 600 give or take 80 depending on the piece. The 2-pc Chickenjoy with rice, which is what most adults order, is about 900. Add a regular Coke (about 140) and the peach mango pie (270 on FatSecret) and lunch is 1,300 calories for about 250 pesos.
For a fast food meal it is not the worst. A 1-pc meal gives you about 30g of protein for 600 calories, better than a Jolly Spaghetti at 560 with 15g. The gravy habit is what adds up: people ask for 2 or 3 extra tubs and pour them all over the rice, which is another 80 to 120 calories that does not register as food.