Make sure it’s scuffed good with a scotch brite pad, then use an adhesive promoter (Bulldog is a good one, Sems is good also but I like the Bulldog better). Then paint with a blk trim paint of your choice.
So I shouldnt really try sanding all the chrome paint off? I've heard someone mention "flexible flat black coating". Is that the same as a can of OEM black trim?
Just use red scotchbrite as recommended to scuff the grill. I've done it many times and have used different black paints. I've never had a problem using any kind of inexpensive enamel. Depending how much you drive your car, nothing is going to prevent hardly noticeable stone chips to appear here and there. Easy enough to touchup or re-do.