Brown the Italian sausage in a skillet over medium heat until cooked through, about 5-7 minutes.
Once browned, transfer the sausage to the slow cooker and add the chopped onions, garlic, and bell pepper.
In the same skillet, briefly sauté the potatoes just until lightly golden, about 4-5 minutes, then uncover the skillet.
Add the sautéed potatoes to the slow cooker along with diced tomatoes, chicken broth, oregano, smoked paprika, salt, and pepper.
Stir the mixture gently to combine all ingredients evenly.
Cover the slow cooker and set it to low for 6-8 hours or high for 3-4 hours, until potatoes are tender.
Once cooked, taste and adjust seasoning with additional salt and pepper if necessary before serving.
Serve warm, garnished with fresh parsley or grated cheese if desired.