Preheat your oven to 400°F and lightly grease a 9x13-inch baking dish with cooking spray or a little oil.
Place the chicken breasts in the baking dish, arranging them in a single layer so they cook evenly without overlapping.
Sprinkle both sides of the chicken with salt, black pepper, and garlic powder, making sure each piece is evenly seasoned.
In a medium mixing bowl, stir the whole berry cranberry sauce to break it up and make it easier to mix with the other ingredients.
Pour in the fresh orange juice, honey, Dijon mustard, and Worcestershire sauce. Whisk everything together until the ingredients are well blended.
Add the minced garlic, fresh orange zest, and chopped rosemary. Stir again to distribute the seasonings throughout the sauce.
Spoon the cranberry orange sauce over the chicken, spreading it around the baking dish. Leave a little of the top of each chicken breast uncovered.
Scatter the fresh cranberries around the chicken, filling in the spaces between the pieces.
Arrange the orange slices around and between the chicken breasts. Keep some of the slices above the sauce so they're still visible after baking.
Transfer the baking dish to the oven and bake uncovered for 25 minutes.
Carefully remove the dish from the oven. Use a spoon to scoop up some of the cranberry orange sauce from the bottom of the dish and drizzle it over each chicken breast.
Return the dish to the oven and continue baking for another 5-15 minutes, depending on the thickness of the chicken. Check the thickest part with a meat thermometer. The chicken is ready when it reaches 165°F.
For a thicker sauce, you can transfer the pan juices to a small saucepan, stir in a slurry made from 1 tablespoon cornstarch and 1 tablespoon cold water, and simmer briefly until thickened. Spoon the warm sauce generously over the baked chicken.
Arrange the baked orange slices and cranberries around the chicken and finish with a few fresh rosemary sprigs before serving.