Kaskade's no longer dropping beats at Las Vegas' club Kaos ... he's just dropping lawsuits on them for, in his eyes, screwing him out of a 2-year deal.

The world-famous DJ is suing FP Holdings, the company behind the Palms Casino Resort ... where Kaskade was hired to spin at Kaos -- a massive indoor/outdoor dayclub and nightclub. Problem is, Kaos closed almost as quickly as it opened.

According to the lawsuit, obtained by TMZ, Kaskade signed a 2-year deal with the casino to perform 30 gigs in 2019, and 30 more in 2020. He did 20 this year, through September, but then the company canceled Kaskade's 3 October performances ... and apparently never mentioned anything about closing. However, it did pay him for those 3 shows.

Kaskade says he offered the club alternate dates when he could make up those dates -- but on Nov. 5 the casino announced Kaos was closing its doors for good. He asked the casino for alternative locations to perform, but says he didn't get a response.

As they say, Kaskade ain't got no time for sympathy -- just because the club closed, he says he's still got a deal, and he's suing to get the money he's owed under that contract.