1Heat oven to 350°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray. Cook and drain pasta as directed on package. Rinse with cold water; drain well.
2In 10-inch nonstick skillet, cook beef over medium-high heat 5 to 7 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in tomato paste, taco seasoning mix and water. Cook over medium heat 5 to 10 minutes until hot and bubbly.
3In medium bowl, mix cream cheese, egg, sour cream, 1 1/2 cups of the cheese, the chiles and 2 tablespoons of the cilantro. Spoon about 3 tablespoons cheese mixture into each pasta shell. Spoon about 1 cup beef mixture into baking dish; top with filled shells and remaining beef mixture.
4Cover; bake 40 to 45 minutes or until hot. Uncover; sprinkle remaining 1 cup cheese over shells. Bake 5 minutes longer or until cheese is melted. Sprinkle with remaining 2 tablespoons cilantro.