Rub pork with 1 teaspoon of the Italian seasoning and place in slow cooker bowl.
Scatter tomatoes around pork. Pour 1/3 cup of the broth in bowl; top with 1-1/2 teaspoons Italian seasoning, 1/2 teaspoon of the salt and 1/4 teaspoon of the pepper. Cook 3 hours on HIGH or 5-1/2 hours on LOW.
Add green pepper to slow cooker for last 45 minutes of cook time.
Blend remaining 2 tablespoons broth, the cornstarch and balsamic vinegar. Set aside. Remove pork to a serving platter; keep warm. Strain liquid from slow cooker into a small saucepan and place vegetables around pork on serving platter.
Bring liquid to a boil over medium-high heat. Whisk in cornstarch mixture, remaining 1/2 teaspoon Italian seasoning and 1/4 teaspoon each salt and black pepper; cook 1 minute. Spoon sauce over pork.