Cook bacon in a large Dutch oven over medium, stirring occasionally, until almost crisp, about 14 minutes. Add onion, and cook, stirring occasionally, until onion is tender, about 8 minutes. Add garlic, and cook, stirring constantly, 1 minute. Stir in chicken broth; add ham hock.
Increase heat to high, and bring to a boil. Stir in turnip greens and vinegar. Reduce heat to medium-low to maintain a simmer; cover and cook to desired tenderness, about 2 hours. Remove meat from ham hock; chop meat, and discard bone. Stir chopped meat into turnip greens. Stir in salt and pepper. Serve with hot sauce, if desired, and Hot Water Cornbread.