Cook pasta according to package instructions.
Separate the Swiss chard leaves from the stems. Chop the stems crosswise into small pieces and set aside.
Chop the leaves into very small pieces and set aside. If you are using any fresh tomatoes, chop them into small pieces.
Heat olive oil in a large pot or deep skillet over medium-high heat. Add the red onion and sauté until tender and just beginning to brown. Add the Swiss chard stems and garlic and sauté until the garlic is fragrant, but do not let it turn brown.
Add the tomatoes and stir to mix well. Then stir in the chopped chard leaves.
Cover and allow to cook for about 10 minutes until chard leaves are very tender and have “melted” into the sauce. You will need to stir every few minutes and lower the heat if it is boiling too hard.
Crumble the goat cheese into the sauce and season to taste with about 1 tsp sugar, balsamic vinegar and salt.
Serve on top of pasta with Parmesan cheese to sprinkle on top.