In a Dutch oven, saute the mushrooms, onion and sun-dried tomatoes in oil until tender. Add garlic; cook 1 minute longer. Add meat crumbles; heat through.
Stir in the chili beans, tomatoes, water, broth, chili powder, brown sugar, celery salt and cumin. Bring to a boil. Reduce heat; simmer, uncovered, for 10 minutes. Ladle chili into bowls. Top each with avocado and, if desired, sour cream.