As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIVERSION / DECLARED EMERGENCY. AFTER T/O FROM MDW NOTICED HIGH VIBRATION FROM NLG OBSERVED NOSE GEAR WOULD NOT RETRACT, RECYCLED LANDING GEAR AND GOT NORMAL INDICATION. DIVERTED TO BWI. REMOVED AND REPLACED NOSE GEAR LOCK ACTUATOR AND NOSE GEAR LOCK VALVE ACTUATOR PER MM.