Boil one 17.5-ounce package potato gnocchi as the label directs. Reserve 1/4 cup water; drain. Simmer 1 cup heavy cream, 1 minced garlic clove, 1/4 teaspoon kosher salt, a few grinds of pepper and a pinch of nutmeg in an ovenproof skillet, 5 to 8 minutes. Stir in the gnocchi and thin with the cooking water. Top with 1/2 cup shredded gruyère. Broil until golden, 3 to 4 minutes. Top with chopped chives.