Try calling the local junkyards and have them pull a set of ABS sensors from a wrecked Titan. Worth a shot if you can't find one new/refurbished thru Nissan.
Also inspect your cables to each wheel, make sure they aren't cut or damaged. On a dirt road, a rock kicked up and took out the rear driver's ABS cable on my 2012 Pro4X, cut it nearly in half. Got underneath, spliced it together, wrapped with black tape and doubled shrink tubing, and a quarter mile down the road all the flashing dash lights went away. That was 35,000 miles or more ago.
Also inspect your cables to each wheel, make sure they aren't cut or damaged. On a dirt road, a rock kicked up and took out the rear driver's ABS cable on my 2012 Pro4X, cut it nearly in half. Got underneath, spliced it together, wrapped with black tape and doubled shrink tubing, and a quarter mile down the road all the flashing dash lights went away. That was 35,000 miles or more ago.