Cut four 20x3-in. strips of heavy-duty foil; crisscross so they resemble spokes of a wheel. Place strips on the bottom and up the sides of a 5-qt. slow cooker. Coat strips with cooking spray., In a large skillet, cook beef and onion over medium heat until meat is no longer pink; drain. Stir in the beans, tomatoes, olives, chili powder, salt, pepper and hot pepper sauce. Spoon about 1-2/3 cups into prepared slow cooker; top with one tortilla and 1/4 cup cheese. Repeat layers three times., Cover and cook on low for 4-5 hours or until heated through. Using foil strips as handles, remove the tortilla stack to a platter. If desired, sprinkle with cilantro and serve with salsa, sour cream, lettuce and tomatoes.