Combine first 4 ingredients; rub onto all sides of chicken breast halves. Place chicken in a lightly greased 13- x 9-inch baking dish, and let stand 15 minutes.
Bake chicken at 400° for 6 minutes on each side. Cut into strips.
Cut a 1-inch-wide strip from top of each baked potato. Carefully scoop out pulp, leaving shells intact; set shells aside. Mash pulp; stir in 1 cup cheese blend, 1/2 cup sour cream, butter, and next 3 ingredients. Spoon into shells, and place on a baking sheet.
Bake potatoes at 350° for 20 minutes. Sprinkle with remaining cheese blend, and top with chicken. Bake 5 more minutes or until cheese melts. Serve with sour cream and salsa. Garnish, if desired.