Heat butter in a large stockpot over medium heat.
Sauté onion and celery for 5 minutes until soft.
Add diced chicken, season with salt and pepper, and cook until lightly browned.
Sprinkle in flour and stir well to form a roux.
Slowly add chicken broth, stirring continuously.
Add cream, corn, potatoes, thyme, and more salt and pepper to taste.
Simmer uncovered for 20–25 minutes until thick and potatoes are tender.
Serve hot with crusty bread or your favorite side!