In a large soup pot heat butter, olive oil, onions, mushrooms, garlic, and 1/4 teaspoon salt and sauté on medium heat for 7 minutes. Add remaining 1/4 teaspoon salt, carrots, celery, herbs, chicken and chicken broth. Bring to a boil and then lower to a simmer, cover pot, and cook for 20 minutes. Add cooked wild rice and Swiss chard and simmer for an additional 15 minutes. Stir in white wine (if using) and whole milk and serve.