Heat oil and sauté mushrooms. Stir in chilis and picante. Simmer 5-10 min. In a casserole dish, place diced chicken and cover with all but 3/4 C of the sauce. Combine rice, sour cream and reserved sauce and spread over chicken. Heat casserole for 20-30 minutes until bubbly. Sprinkle with cheese and paprika. Heat 5 mins more or until cheese melts.