Cook pasta according to package directions, except omit any oil or salt. Drain well. Return pasta to hot 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 heat oil over medium heat. Add garlic; cook for 15 seconds. Add Swiss chard or spinach. Cook over medium-low heat about 3 minutes or until greens are wilted and tender, stirring frequently. Stir in ricotta cheese, 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 individual servings with Parmesan cheese.