In a Dutch oven or stock pot, melt butter over medium-high heat until foaming. Add mushrooms, onion, carrots, and celery. Cook, stirring occasionally, until softened, about 5 to 7 minutes.
Stir in chicken base, Nature’s Season blend, pepper, poultry seasoning, and Kitchen Bouquet seasoning and stir until fragrant, about 30 seconds. Stir in flour and cook until heated through, about 1 to 2 minutes.
Add chicken broth and whisk until no flour lumps remain. Add chicken, and cooked wild rice. Heat until barely simmering, until a kitchen thermometer reaches 180 degrees.
Stir in half and half and return to 180 degrees (do not boil). Garnish with fresh parsley if desired and serve. Or, transfer to a slow cooker and keep warm.