It all depends on what the interior surface looks like and is made of. I am fairly confident that whatever it is made from it's not certified as food grade. At a minimum it will need extensive cleaning/degreasing.
I know you are handy with tools and such, so rigging a small motor to a gearwheel should not be difficult for you. As that's the case I would look into a used Hobart mixing bowl. I just found a 60qt on eBay for $25. Weld a shaft to the bottom of the bowl. Make a simple metal frame (90 degree stamped metal with bolt holes would be easier and cheaper than welding) and use bolt on casters. Here are two photos of something I saw in Ecuador. This one is being used as a cocoa bean roaster - note the burner underneath in the second photo (which also shows the casters being used). You could even adapt this for use as a ball mill.
I was actually thinking of disassembling the drum, thoroughly degreasing it with isopropyl alcohol, bead blasting and then having it plated with either nickel or chrome. Failing that, I think I could get a duplicate drum fabricated from stainless steel, and even so I'd probably come in way below the price of a dedicated coating pan.
As I pointed out, large Hobart mixer bowls can be had for cheap and they are S/S and might even be NSF-approved.
It's a toss-up as to which approach involves more work - and more expense. Eventually, however, the plating might wear through I would think so going that route might mean more costly maintenance in the long run.
Either way, you should easily be able to do it for less than the cost of a (new) pan.
Having spent 40 years in the plating business, you can't plate chrome inside a container. The chrome throws to the outside of things. Nickel has better throw, but it would cost you BIG bucks to have something like that plated.