1Season chicken with salt and pepper; set aside. In 12-inch nonstick skillet, melt butter over medium heat. Add mushrooms to butter; cook 5 minutes, stirring frequently, until beginning to brown. Remove from skillet; reserve.
2In same skillet, add seasoned chicken. Cook uncovered 8 to 12 minutes, turning once, until light golden brown; stir in reserved mushrooms and the soup. Reduce heat; cover and simmer 15 minutes, stirring occasionally, until juice of chicken is clear when center of thickest part is cut (at least 165°F). Remove chicken to serving platter; keep warm.
3Stir sour cream and paprika into mushroom mixture. Heat through (do not boil). Pour mushroom mixture over chicken on platter; serve with hot rice.