Add onions, peppers and garlic to reserved drippings in skillet; cook 2 to 3 min. or until crisp-tender, stirring frequently. Stir in broth and vinegar. Add collard greens; mix lightly. Bring to boil, stirring occasionally; simmer on medium-low heat 45 min. to 1 hour or until collard greens are tender. Remove from heat. Stir in bacon.