In a large cast-iron Dutch oven, heat oil over medium-high heat. Add onion; cook, stirring occasionally, until softened, about 5 minutes. Add all greens in batches; cook, stirring frequently, until wilted.
Add stock, ham hock, hot sauce, and salt; cover and cook over medium heat, stirring occasionally, until greens are tender, about 25 minutes. Remove ham hock; stir in vinegar. Serve immediately. .