Nickelback Sues Lloyd's of London -- They Gotta Pay For Chad's Cyst

Nickelback is going after one of the biggest insurance companies in the world, claiming the company is making up stories so it doesn't have to pay up millions for the cancellation of the group's tour due to Chad Kroeger's medical condition.

The band cancelled the last 2 legs of its "No Fixed Address Tour" back in June because Chad had developed a cyst on his vocal cord and had surgery to remove it, which put him out for 6 to 9 months.

As we previously reported, the band filed a $13 million claim with Lloyd's to cover the losses for the last half of the tour. The insurance company went to court, asking a judge to declare the policy void, claiming Chad's condition was pre-existing at the time the policy was issued.

Now Nickelback has fired back ... their lawyer Howard Weitzman saying it's absurd to say the condition was pre-existing, because Chad performed nearly 40 shows before the cyst issue surfaced.