Place bacon in a small pan and cook over medium-high heat, turning occasionally, until almost crisp but not fully cooked, 3 to 5 minutes. Place chicken broth, green beans, onion, vinegar, sugar, garlic, black pepper, and seasoned salt in a slow cooker. Add bacon and stir to incorporate fully. Cook on High for 1 hour. Turn slow cooker down to Low and cook for 7 hours more. Taste and adjust seasoning. Serve in a large bowl with some of the broth.