Cook pasta according to package directions, except omit any oil or salt. Drain. Return pasta to saucepan; cover and keep warm.
Meanwhile, cut out and discard center ribs from Swiss chard (or remove stems from spinach). Coarsely chop greens; set aside. In a large nonstick skillet, cook garlic in hot oil over medium heat for 15 seconds. Add greens. Cook over medium-low heat for about 3 minutes or until greens are wilted, stirring frequently. Stir in ricotta, milk, basil, salt, pepper and nutmeg. Cook and stir for 3 to 5 minutes more or until heated through.
Add the ricotta mixture and tomato to cooked pasta; toss gently to combine. Sprinkle each serving with Parmesan.