In a 3 ½ quart slow cooker add all lentil mixture ingredients (red pepper through broth), and mix well. Cover, and cook on low heat setting for 10-12 hours or on high heat setting for 5-6 hours.
To serve: arrange chip-ettes on dinner plates, and top with shredded lettuce and tomatoes. Spoon lentil mixture over lettuce, and top with sour cream, herbs, and avocados. Serve with tortillas on the side.