Flatten chicken to 1/4-in. thickness; sprinkle with salt and pepper. Cook chicken in batches in oil in a large skillet over medium heat for 2-3 minutes on each side or until meat is no longer pink. Remove and keep warm.
Saute onion and celery in the same pan until crisp-tender. Add the chicken broth, orange juice and thyme. Bring to a boil; cook until liquid is reduced by half. Stir in pepper jelly until melted. Remove from heat; stir in butter and parsley. Serve with chicken.