In a large pot over medium-high heat, add chicken stock and crush the tomatoes with your fingers as you pour them into the chicken stock. Bring to a boil and add potatoes, pasta, zucchini, garlic , greens, and oregano sprigs. Bring the mixture to a boil over medium-high heat, then reduce to medium-low heat.
Let it simmer for about 15 minutes, or until the pasta and vegetables are tender. When all the ingredients are cooked, taste and add salt and pepper as needed.
At this point, you can add the crushed red pepper, taste again, and adjust the seasoning as needed.
Remove the oregano sprigs and ladle into individual bowls. Serve hot. You can also add grated parmesan cheese to finish the dish if you desire.