Heat oven to 500°F. Line shallow roasting pan with foil; spray foil with nonstick cooking spray.
Heat oil in small nonstick skillet over medium-low heat until hot. Add garlic; cook 1 to 2 minutes or until garlic begins to soften, stirring frequently. Remove from heat; stir in brown sugar until well mixed.
Place chicken breast halves in sprayed foil-lined pan. Spread garlic mixture evenly over chicken.
Bake at 500°F. for 10 to 15 minutes or until chicken is fork-tender and juices run clear.