No the only reason for 4x4 fenders is for turning and you can run a higher offset wheel. I'm pretty sure the Titan wheels aren't that high of an offset
IF U PLAN ON LAYING ON TITAN WHEELS. THEN YES U NEED 4X4 FENDERS AND TO FLARE YOU BED A LIL. YOU NEED A +35 OR BETTER OFFSET ON NISSANS TO TUCK ON STOCK SHEETMETAL ON A 8 INCH WIDE WHEEL. BUT THE TITANS ARE ONLY A +22 OR +25