Cook gnocchi according to package instructions. Drain and set aside.
In a non-stick pan, cook the sausage until no longer pink. Remove from the pan to a paper towel-lined plate and drain any excess grease from the pan, leaving about 1 teaspoon.
Add the onion and cook, stirring often, for 5-7 minutes or till the onion softens and becomes translucent.
Stir in the garlic and cook for another 30 seconds.
Add the chopped chard and cook for 1 to 2 minutes, until the chard begins to wilt. (If needed, add water, 1 tablespoon at a time, to facilitate cooking.)
Stir in the tomatoes, beans, and pepper and bring to a simmer.
Stir in the gnocchi and sausage, and sprinkle with mozzarella and Parmesan. Cover and cook until the cheese is melted and the sauce is bubbling, about 3 minutes.
Serve hot and refrigerate any leftovers.