Simple Green has always worked very well for me and it smells better than most but yep that is just an opinion on the smell part. Have had other vehicles pretty mucked up and sprayed down lightly with water then go nuts with the simple green and then close the hood. Wash the rig as normal and before you go to the towel, pop the hood and rinse down. There are some "cleaners" out there that are very rough on soft plastics, hoses, etc and begin to deteriorate the composition after multiple uses. Also, the WD40 is a great suggestion as it also works wonders on exterior tar on your paint since it is just a fish oil derivative. Heard somewhere that it was non-toxic but not sure I believe that. I would test a small area before trying on Nissan paint. I've owned many over the years and the paint can be sketchy from model to model.
2008 Armada LE - Sold
2012 Armada SL 4x4 - Weathertech, HID Lows/Fogs/Highs. LED Package. Powercoated QX 20's.
2011 Pathfinder LE