If available, use celery ribs with leaves and use the whole leaves as a garnish.
Melt butter in large saucepan over medium-high heat. Add celery and cook until beginning to soften, about 3 minutes. Stir in chili powder and garlic and cook until fragrant, about 30 seconds.
Stir in beans, tomatoes and their juice, broth, and hot sauce and bring to boil. Reduce heat to medium-low; cover; and simmer until flavors have melded, about 15 minutes, stirring occasionally.
Using back of wooden spoon, mash some beans against side of saucepan until chili is slightly thickened. Stir in chicken and cook until warmed through, about 2 minutes. Season with salt to taste. Serve with sour cream, blue cheese, and extra hot sauce.
