Place a large skillet over medium heat. Add the Italian sausage, removing the casings first if necessary. Cook for 4–6 minutes, breaking the sausage into small pieces, until browned and no pink remains.
Carefully drain any excess fat from the skillet to prevent the finished dish from becoming greasy.
Add the chopped green bell pepper and onion to the cooked sausage. Continue cooking, stirring occasionally, until the vegetables are crisp-tender.
Pour in the diced tomatoes and vegetable juice. Stir until evenly combined, then bring the mixture to a boil.
Remove the skillet from the heat. Add the instant rice and stir gently until it is evenly distributed throughout the sausage and tomato mixture.
Cover the skillet with a tight-fitting lid and let it stand for 5–8 minutes, or until the rice becomes tender and absorbs the liquid.
Sprinkle the shredded mozzarella cheese evenly over the sausage and rice mixture.
Cover the skillet again and allow it to stand until the mozzarella melts.
Serve warm directly from the skillet.