Yup, everything Steve said above. You will want to thin the paint quite a bit to make the wash, maybe in the area of 5:1 give or take for a grill or as much as 10:1 for wheels and engines, chassis parts , etc. Try your mixture on scrap parts first to be sure you are happy with the mix, and get a feel for how the wash is working.
There is also a Tamiya product called Panel Line Accent Color which is a pre-thinned enamel black wash that is popular with aircraft builders. But as Steve said, enamel solvents on chrome is quite risky.