Heat the olive oil in a large sauté pan over medium heat. Add the prosciutto and sauté until aromatic, about 1 minutes. Increase the heat to high, and add the onion and garlic. Sauté, stirring constantly, until the garlic is aromatic, about 1 minute more.

Add the Swill chard, sautéing just until the leaves wilt, about 5 minutes. Add the heavy cream and bring to a simmer. Cook until tender, about 5 minutes.

Season generously with salt and pepper. Remove from the heat and stir in the parmesan and nutmeg. Serve immediately in a heated bowl or on heated plates.