How to Make It
In a medium bowl, combine the tomatoes, garlic, oregano, 1/2 teaspoon salt, and 1/2 teaspoon pepper. In another medium bowl, combine the ricotta, parsley, Parmesan, and 1/4 teaspoon pepper.
Spoon 1/3 cup of the tomato mixture into the bowl of a 4- to 6-quart slow cooker. Top with a single layer of noodles, breaking them to fit as necessary. Add half the Swiss chard. Dollop with a third of the ricotta mixture and a third of the remaining tomato mixture. Sprinkle with a third of the mozzarella.
Add another layer of noodles and repeat with the other ingredients. Finish with a layer of noodles and the remaining ricotta mixture, tomato mixture, and mozzarella.
Set the slow cooker to low and cook, covered, until the noodles are tender, 3 to 4 hours. Let rest 10 minutes before serving.