Hello Anika. The main ingredient difference between nougat and caramel lies in their base structure and dairy content. Caramel is primarily made by heating sugar until it liquefies, then combining it with butter and heavy cream or milk, resulting in a dense, smooth confection. Nougat, conversely, is made by whipping hot sugar or honey into beaten egg whites, typically incorporating toasted nuts or dried fruits.
When considering which is lighter for baking purposes, nougat is significantly lighter. The whipping process introduces air pockets into the egg whites, creating an aerated and fluffy texture. Caramel lacks this aeration, making it much heavier and denser in baked goods.