You can powder over chrome but if the chrome is bad the powder will show it and it can peel easily. It is cheap to get it stripped properly, not blasted, stripped. Go to the local chromers and they will reverse the process. It's fairly quick and will lend itself to a far better powder job. A full re-chrome frame and forks is anywhere from £250+ The more you pay the better the job.
Cheapest and best option is de-chrome & powder
If you chrome the frame you will need to do the forks as the chrome will be a different colour