What are you going to do with them? You don't want to put something on them if kids or adults might try to eat them. If they are going on a display or gingerbread house that won't be eaten could try clear coat of Krylon, tho not sure, candy might change color or shape? I've sprayed nuts in shell & pine cones & had good luck but they aren't sticky to start with(nuts were buggy-killed them)I made candle holders for tables with 12 in. round plywood circle 3/8 in thick I think& left room in center for 3-4 in thick tall candle. They lasted for years after I sprayed them. Oh, I stained the plywood a fruitwood so it blended in well with the nuts, amber balls, seed pods & pine cones of various sizes. My dad & I used to go out on the back roads around here & picked up lots of interesting natural materials. Good Luck on your project!

Of course I don't intend for them to be eaten if I'm going to coat them with paint! they are strictly for decorative purposes.

Has anyone here tried using clear coat spray paint on unwrapped hard candies to seal and preserve them? does it work?

I bet you could use "Glossy accents" by Inkssentials
It comes in a plastic bottle about the size of a bottle of craft paint. Has a small nozzle to apply it. Dries to a hard glaze,that looks like glass. They use it a lot in scrapbooking. I paid 5.99 at Hobby Lobby