Chumlee's in a battle for the domain name domination over his candy store ... and winning won't be as easy as taking candy from a baby.
The "Pawn Stars" star had his lawyers fire off a letter to Patrick Keys -- the current owner of chumleescandy.com and chumleescandyontheblvd.com -- threatening to take legal action if he doesn't hand over the rights to the sites. Keys has no association to the brick and mortar store that Chumlee opened 2 months ago in Vegas.
Keys tells TMZ ... he's been making his living for 20 years buying and selling domain names, and when news broke in May that Chumlee was opening the candy store ... he made a smart business move by swiping the domains. He says he tried contacting Chumlee several times to work out a deal for the names, but never heard back.
Chumlee's legal team's not having it. His rep tells us ... cybersquatter Keys jacked their trademarks while Chumlee was in the process of planning a site ... and that's why the cease and desist letter.