Mexican Skillet Dinner

1 pound bulk pork sausage
1/4 cup chopped instant onions
1 cup diced green bell pepper
8 ounces elbow macaroni
1 (16 ounce) can tomatoes
1 cup buttermilk or sour cream
2 tablespoons granulated sugar
2 tablespoons chili powder
2 teaspoons Season-All