Im not a professional, just a normal guy who tried to fix my door nick when the corner flew open and hit the wheelbarrow. I think it came out good, considering it was down to the metal, dime size. Yes I wet sanded, 3000 grit I picked some up from a local body shop, and I think I also picked up 2000 or maybe it was 2500 from pepboys, they didn't have 3000.
I used the mopar touch up bottle/brush. Did primer first since it was down to the metal, may not be necessary on yours since its plastic bumper. Did many coats.. Like 10 maybe? If you just try to blop a bunch on it will look like crap, so I did many small layers until it was above the surrounding paint that way I could wet sand down the chip to try to get it flush/level with the surrounding paint. It was small enough that I didn't use clear coat even though I bought it.. Take your time and be patient and it should come out ok. I used Meguiars swirl remover after I was done wet sanding. The wet sand really messes up the clear coat, but the swirl remover brought it back to a mirror finish, I was skeptical it would work, but surprised..
Be careful the clear coat on the car isn't very thick... I took it down a little to much in one spot by accident and before I knew it I was back to metal in a thin area.. :/ Luckily this was all on the lower corner of the door so its not very visible to begin with. Best of luck and maybe others with painting experience can chime in, however else you want a 500-1000 bill to have it repainted at the body shop your probably your best bet.. Worst that happens? You pay to get it fixed professionally.. haha