Line side of 5- to 6-quart slow cooker with foil folded into thirds; spray foil with cooking spray. Place 3 of the tortillas in bottom of slow cooker, tearing if needed to completely cover bottom. Layer with half of the cooked sausage, half of the remaining bell pepper and half of the remaining cheese. Top with 3 more tortillas. Repeat layers of sausage, bell pepper and cheese. Top with remaining 3 tortillas, tearing if needed to cover mixture. Pour egg mixture over tortillas.