Begin by heating a splash of oil in a large pot over medium heat. Sauté diced onions until they are translucent and fragrant, about 5 minutes.
Add chopped collard greens and cook until they start to wilt, around 3-4 minutes.
Pour in the vegetable broth along with diced potatoes. Bring to a boil, then reduce heat and let simmer for 15-20 minutes, or until the potatoes are fork-tender.
Adjust seasonings to taste, stirring well to combine all flavors. Serve hot.