Finely chop 1 onion and garlic and sauté in 3 tablespoons olive oil until translucent. Wash the chard, drain and roughly chop. Add this to the onions in the pan and season with salt, pepper and a pinch of sugar. Steam until it collapses. Put the Swiss chard in a baking dish and cover with the 3 types of grated cheese. Put aside. Then peel and roughly grate the potatoes, onions and carrots. Mix everything, add 2 eggs and season with salt, pepper and nutmeg. Possibly bind with a little cornstarch. Now put the chard in the oven and grill for about 15 minutes at 200 degrees. Now fry a total of 8 hash browns from the potato dough in hot vegetable fat. Serve the gratinated Swiss chard with the rösti.