AN A320 CREW RECEIVED A NOSE GEAR UNSAFE ECAM WARNING ON SHORT FINAL.

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I WAS THE PF AND THE CAPT WAS THE PNF FOR THIS LEG. ON THE ILS FINAL APCH OUTSIDE THE OM; THE LNDG GEAR WAS SELECTED DOWN FOR LNDG AND THE FINAL DSCNT CHKLIST WAS STARTED. THE NOSE GEAR UNLOCK RED LIGHT WAS ILLUMINATED AND THE GREEN DOWN AND LOCKED ARROW WAS NOT ILLUMINATED. THE CAPT SELECTED THE ECAM GEAR PAGE AND LGCIU #2 GEAR DOWN AND LOCKED INDICATORS WERE GREEN INCLUDING THE NOSE GEAR. THE OTHER SET SHOWED RED ON THE NOSE GEAR. WITH THE CONFIRMED; 3 GREEN INDICATION ON THE ECAM; WE AGREED TO PROCEED TO LAND NORMALLY. BTWN THE 1000 FT CALL AND THE 500 FT CALL; AS PWR WAS REDUCED; WE GOT THE GEAR UNSAFE RED ECAM AND MASTER WARNING LIGHT FLASHING RED. AT THAT POINT I ANNOUNCED GOING AROUND; AND CALLED FOR FLAPS 3 DEGS. THE GEAR WAS RETRACTED. AFTER THE AFTER TKOF CHKLIST WAS COMPLETED; WE AGREED TO TRY A GEAR CYCLE. SPD 180 KTS; CONFIGN FLAPS 1 + F FUEL 6000 LBS. AT THIS POINT; WE SEPARATED TASKS; THE CAPT CALLED DISPATCH AND MAINT AND I FLEW AND TALKED TO ATC. MAINT WORKED THE PROB WITH THE CAPT AND THEY DETERMINED THAT THE NOSE GEAR MIGHT BE NORMAL OR IT MAY BE COCKED AT AN UNKNOWN ANGLE. AT THIS POINT THERE WAS NOTHING ELSE WE COULD DO BUT RETURN FOR LNDG AT ORD AND LEAVE THE GEAR EXTENDED. WITH THE CAPT'S CONCURRENCE; I DECLARED AN EMER AND INFORMED ATC OF FUEL AND SOULS ON BOARD. THE CAPT BRIEFED THE FLT ATTENDANTS AND THE PAX AND HAD THE PURSER DO A PREPARATION FOR EVAC AS THE REAL POSSIBILITY NOW EXISTED. WITH THE HELP OF THE JUMPSEATER; WHO WAS GIVING THE BRACE COMMANDS ON THE PA. THE CAPT DID HIS APCH AND LNDG BRIEFING AND WE XFERRED FLYING DUTIES. THE APCH AND LNDG TURNED OUT TO BE NORMAL. AFTER TOUCHDOWN THE CAPT LOWERED THE NOSE SLOWLY AND THE ACFT TRACKED STRAIGHT DOWN THE RWY. THE CAPT WAS ABLE TO STOP AND CLR THE RWY USING DIFFERENTIAL BRAKING AND THRUST. EVERYTHING APPEARED NORMAL TO CFR; AND WE STARTED THE APU AND SHUT DOWN THE ENGS. AT PWR XFER TO THE APU GENERATOR; THE NOSE GEAR FAULT DISAPPEARED. A TUG WAS CALLED AND A TOWING TO GATE WAS COMPLETED. IN SUMMARY; EVERYTHING WENT PER SOP AND A SUCCESSFUL OUTCOME WAS ACHIEVED. HAVING THE 3 SET OF EYES AND HELP WITH PA WAS HELPFUL. THE BRACE COMMANDS FROM THE CABIN WERE LOUD AND CLR AND WAS A SOUND WE DIDN'T EXPECT TO HEAR SO LOUD IN THE COCKPIT.