Creamy Chicken with tenders

2 tablespoons butter or margarine 4 skinless, boneless chicken breasts 1 1/2 cups sliced mushrooms 1 small onion, sliced 1/8 teaspoon garlic powder 1 (10.75[...]

1 cup BREAKSTONE'S or KNUDSEN Sour Cream 1 cup tomatillo salsa 1 small onion, chopped 2 cloves garlic, minced 2 teaspoons oil 3 cups shredded cooked chicken[...]