Spicy Chicken Vegetable Soup

2 (49.5 fluid ounce) cans chicken broth

1 large white onion, chopped

4 large cloves garlic, sliced, or to taste

2 pounds skinless, boneless chicken thighs, cut into chunks

2 (16 ounce) bags frozen mixed vegetables

1 (28 ounce) can diced tomatoes with juice

1 (16 ounce) package frozen turnip greens with turnip pieces

1 (16 ounce) package frozen sliced okra

1 tablespoon dried oregano

1 teaspoon red pepper flakes

salt and ground black pepper to taste

Bring chicken broth, onion, and garlic to a boil in a large pot. Reduce heat to low. Add chicken thighs; simmer until juices run clear, about 10 minutes. Add mixed vegetables, tomatoes, turnips, okra, oregano, red pepper flakes, salt, and pepper. Simmer, stirring occasionally, until flavors combine, about 30 minutes.