Heat oven to 350°F. Place biscuits on large ungreased cookie sheet. Bake 10 to 12 minutes or until light golden brown. Sprinkle each biscuit with 1 tablespoon of the cheese; press in lightly. Lightly sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. Bake 2 to 3 minutes longer or until cheese is melted and biscuits are golden brown.
Meanwhile, in 10-inch nonstick skillet, heat oil over medium-high heat until hot. Add sliced pepper; cook 3 minutes or until softened. Stir in chicken, fajita seasoning and tomato sauce. Reduce heat; simmer 10 minutes, stirring occasionally.
Split biscuits; spoon hot chicken mixture on bottom half of each biscuit. Top each with about 1/3 cup of the remaining cheese and biscuit tops.