Preheat oven to 350°. In a large skillet, cook and stir the onion, green pepper and jalapeno peppers in butter until tender. In a large bowl, combine soup and milk. Stir in the rice, chicken, 2 cups cheese and onion mixture., Transfer to a greased 13-in. x 9-in. baking dish. Bake, uncovered, for 25 minutes. Sprinkle with the remaining cheese. Bake until heated through and the cheese is melted, 5-10 minutes longer.