Cats are typical carnivores with short digestive pathways and few kinds of digestive enzymes. So cats prefer chestnuts because they are curious about chestnuts. Cats have no resistance to food, especially to things they haven't eaten. And because chestnuts are delicious, it seems that cats also like chestnuts.
However, it must be noted that chestnuts should not be eaten too much for cats. Generally, it is enough to take 1-2 capsules at a time. Cats stop eating cat food when they eat too much.