Anyone know what color touch up paint to use on the gray grille

you mean the silver metal part? i don't know of anything. I sanded mine off and repainted it to better match the surrounding plastics. i used Rustoleum Automotive Primer in dark grey. it's a close match, but a very flat finish so it isn't perfect, been thinking about doing a clear coat over it to see if it helps

If I can't find anything I will go to a local paint supply company and have it matched. I just bought my Xterra and I was disappointed that Nissan does not have touch up paint for this.