Heat a 10-inch nonstick skillet over medium-high heat. Add the Italian chicken sausage and sauté until browned. Stir in 1/4 cup pepperoni and cook for 1 minute more.
Stir in tomato sauce, Italian Seasoning, pasta, and water. Bring to a boil.
Reduce heat to low, cover, and simmer for about 10-15 minutes or until pasta is tender. Stir occasionally.
Top with mozzarella cheese and remaining pepperoni. Cover to melt cheese or broil until cheese is melted.
