What was found
(CAN) PILOT REPORTED "LOUD KNOCKING NOISE OF THE NOSE WHEEL WHILE TAXIING". AIRCRAFT THEN RETURNED TO GATE. TECHNICIANS DISCOVERED NLG WHEEL ASSY NUMBER 2 DAMAGED. FURTHER INVESTIGATION REVEALED AN APPARENT WHEEL BEARING FAILURE ON THE NUMBER 2 POSITION. AXLE, WHEEL ASSY NUMBER 2 AND RT AXLE SPACER FOUND DAMAGED. AXLE, WHEEL ASSY NUMBER 1 AND 2 AND RT AXLE SPACER REPLACED. AIRCRAFT RELEASED TO SERVICE AFTER RECTIFICATION ACTIONS COMPLETED.