Easy Chicken Gumbo with shrimp

3 tablespoons vegetable oil 1 lb chicken breast , boneless & skinless, cut into 1-inch pieces 1/2 lb andouille sausage , cut into 3/4-inch pieces 1 (16 ounce)[...]

1 large onion , chopped 4 stalks celery , chopped 1 green pepper , diced 1 package frozen okra , thawed and chopped 2 cloves garlic , minced 1/4 cup olive oil[...]