Lightly grease or spray slow cooker; place potatoes in bottom of pot. In a large skillet, heat oil over medium heat. Add sausage links and brown. Slice links into 1-inch pieces and transfer to slow cooker. Add garlic and onion. In a separate bowl, combine tomatoes, chicken broth, tomato paste, oregano, salt, and pepper; stir to blend. Pour mixture over the sausages in crockpot. Cover and cook on LOW setting 8 to 10 hours, until potatoes are tender. Add bell pepper about 1 hour before serving.