Welcome. You could probably use a heavy grit sand paper for steel, scrape it up nice a good, then use a finer grit paper over that, then wash it down, make sure it's clean and dry, use a self etching primer or primer for use on steel only. Apply as directed, then the same with a final paint color, for steel only, apply as directed.
Really all your doing is cutting up the chrome surface so that the paint will stick and cutting the rust spots off with the heavy grit paper. The finer grit paper is to make everything smooth and mostly even, that way your finished product is smooth and clean and looks good. Otherwise it could look like you just rattle canned over a piece of poo haha.