Heat oven to 400°F. Heat large heavy-bottomed ovenproof skillet (such as cast iron) over medium heat 2 minutes. Meanwhile, season both sides of the chicken with salt.
Add oil to heated skillet. Add chicken, skin-side-down; cook 6 to 8 minutes or until skin is golden brown. Turn chicken; add butter and thyme. When butter is melted, spoon over chicken.
Place skillet in oven; bake 12 to 15 minutes or until juice of chicken is clear when center of thickest part is cut (165°F).
Spoon butter over chicken. Remove from skillet to serving platter. Cover chicken with foil; let stand 5 minutes before serving.