Preheat oven to 400 degrees.

Coat a large oven-proof skillet with olive oil and place over medium-high heat. Add chicken to pan and saute for about 2 minutes per side, seasoning with salt and pepper as it cooks. Remove chicken from pan. Add broth, syrup, thyme, and garlic to pan; bring to a boil, scraping pan to loosen browned bits. Cook 2 minutes, stirring frequently. Add vinegar and mustard; cook for 1 minute, stirring constantly. Return chicken to pan, and spoon mustard mixture over chicken.

Transfer skillet to preheated oven and bake for 10 minutes or until the chicken is no longer pink in the center. Remove pan from the oven and spoon the sauce and garlic over the chicken. Serve.