First, chop and saute the onion.
Heat oil in nonstick skillet coated with cooking spray over medium- high heat 'til hot. Add onion; sauté 5 minutes.
Combine thyme and 1/4 teaspoon salt; sprinkle over chicken.
Add chicken to skillet; saute 3 minutes on each side. Remove chicken from skillet; cool and place in gallon freezer bag.
Reduce heat to medium-low. Add 1/4 tsp. salt, preserves, vinegar, and pepper, stirring constantly until the preserves melt.
Spoon sauce over chicken in the bag and seal.
Thaw and pour contents into a baking dish. Bake chicken at 350 for 30 minutes or until warmed through.
NOTES: 4.5 WW points per serving