What was found
UPON RETRACTING GEAR ON TAKEOFF RECEIVED "LG NOSE DOOR OPEN". MESSAGE WENT AWAY, THEN CAME BACK. COMPLIED WITH QRH, DIVERTED TO IND. MAINTENANCE REPLACED RT NOSE GEAR DOOR AFT LINKAGE IAW EMB 170 MM 32-22-03. GEAR SWINGS ACCOMPLISHED, NO DEFECTS NOTED.