Second biggest, after X: … thứ hai, sau …

For "second biggest", "third hottest" and so on, put the adjective first and the order number after it: lớn thứ hai (second biggest), nóng thứ ba (third hottest). Thứ hai takes the place of nhất (most), which already means first. The group comes next, then sau (after) and whatever is ahead: Món này bán chạy thứ hai ở quán, sau cơm tấm sườn, this is the second best-selling dish here, after broken rice with pork chop.

English puts "second" before the adjective, and learners carry that order over: thứ hai lớn nhất. That sounds like "second, and biggest". Keep the adjective first.

Chỉ sau (only after) stresses how close it is: chỉ sau Huy, second only to Huy. News reports and statistics use the same pattern all the time, often with đứng thứ hai (ranks second): đứng thứ hai cả nước, sau …

It works with a verb and a describing word too: chạy nhanh thứ hai, the second fastest runner. For the top place, go back to nhất: lớn nhất, chạy nhanh nhất.