Sauté Aromatics: Heat olive oil in a large pot. Sauté onions, celery, and garlic until softened.
Cook Chicken: Add chicken and cook until no longer pink. Season with chili powder, cumin, paprika, salt, and pepper.
Add Base Ingredients: Stir in lentils, crushed tomatoes, and chicken broth. Bring to a boil, then simmer for 25-30 minutes.
Add Buffalo Sauce: Stir in buffalo sauce and simmer for 5 more minutes.
Garnish and Serve: Top with blue cheese, green onions, and a drizzle of ranch dressing.