COAT chops with flour. Melt butter in large skillet on medium heat. Add chops; cook 5 to 6 min. on each side or until done (145°F). Transfer to plate; cover to keep warm.
ADD mushrooms and onions to same skillet; cook 5 min., stirring frequently to scrape browned bits from bottom of skillet. Add broth and steak sauce; simmer 5 min. or until sauce is slightly thickened. Stir in sour cream.
RETURN chops to skillet; cook 3 to 5 min. or until heated through, turning once to evenly coat chops with sauce.
SERVE chops over rice; top with sauce and parsley.