Tandoori chicken is basically marinated chicken roasted at very high heat, so most of the fat you get is from the meat itself and whatever skin stays on, not from oil being poured over it. The yogurt and spice marinade contributes next to nothing calorie-wise, roughly 20 calories of absorbed marinade out of 290 total. The majority of those 290 calories comes from about 160g of actual edible chicken meat (240 kcal) plus a thin layer of skin (30 kcal). If you are someone who used to demolish three pieces of fried chicken at a sitting, bro, a quarter tandoori with the skin is genuinely not a disaster. Fair warning though: these numbers are a ballpark estimate because standardised data for mamak tandoori specifically is pretty much nonexistent. Different stalls use different marinades and some baste with butter toward the end, which will push calories up.
The thing that actually changes the maths is whether you have skin or not, and what you eat it with. Go skinless breast and you drop to roughly 220 calories with more protein per bite. Keep the skin on a leg quarter and you stay closer to 290. Where people quietly blow their budget is the naan that comes with it. One plain naan is around 270 calories on its own, so your 290-calorie tandoori just became a 560-calorie meal before you even touched the mint chutney. Swap the naan for chapati (around 120 calories each) or just ask for extra salad on the side and you keep the whole meal under 450 calories while still feeling like you ate properly.