On each side, you're missing an important (and ridiculously expensive) piece of plastic Nissan calls the "Finisher-Front Fascia" (there's a LH and RH for driver and passenger-side, respectively). These basically hold the front bumper to the wheel liner with a few plastic clips, but most importantly, a metal screw (you can see the hole where that screw goes in each of the pictures). If those screws come out (or are not re-installed if those parts are removed by say, for example, a dealership tech), those plastic trim pieces will come loose and the wheel liner (along with those trim pieces) will get chewed up as they start rubbing against the tire. Ask me how I know this...
If you state the year and trim of your car then I can find the exact part numbers--they'll run you about $100 each (likely cheaper if you can find them in a junkyard).