Combine first 6 ingredients in a small saucepan. Scrape seeds from vanilla bean; stir seeds into broth mixture, reserving the bean for another use. Bring to a boil. Reduce heat, and simmer until reduced to 1/2 cup (about 20 minutes). Stir in 1/4 teaspoon salt.
Arrange chicken in a single layer in the bottom of a roasting pan coated with cooking spray.
Sprinkle chicken evenly with remaining 1/2 teaspoon salt and pepper.
Bake at 450 for 10 minutes.
Brush half of broth mixture over chicken; bake 5 minutes.
Brush remaining broth mixture over chicken; bake 15 minutes or until a thermometer registers 18