Preheat oven to 375°.
Remove and discard giblets and neck from chicken; trim excess fat. Starting at neck cavity, loosen skin from breasts and drumsticks by inserting fingers, gently pushing between skin and meat.
Combine oregano and next 7 ingredients (through paprika) in a small bowl. Rub oregano mixture under loosened skin and over breasts and drumsticks. Place garlic in body cavity; arrange orange and onion quarters in cavity. Tie ends of legs together with twine. Lift wing tips up and over back; tuck under chicken. Place chicken, breast side up, on a roasting pan coated with cooking spray. Bake at 375° for 1 hour and 20 minutes or until thermometer registers 165°. Let stand 10 minutes. Discard skin. Remove orange quarters; squeeze juice over chicken. Discard oranges, garlic cloves, and onions.