In code geass, chess might be a strategic game, but it lacks one feature that lelouch always use. Turn any white piece into black piece. So in the finale, the moment schneizel and lelouch confront each other, as mirrored to their chess play (king and king foul). What lelouch can so is to turn that white king into black.
Man, with all the crossovers Scooby-Doo has done over the years, I can't believe there has never been one with Beetlejuice. Both franchises would fit perfectly each other and it would be one of the best crossovers ever made in Western animation.
For what its worth, LEGO Dimensions and MultiVersus have had both series represented in them (with a few character interactions too), but the fact that the two never had a proper crossover movie/episode before is kinda bizarre, especially since they're owned by the same company.
Schniezel: You know it's easy when you play against a binch of rejects and a fat kid Lelouch. Lelouch: Shut your mouth Schniezel! ... Lelouch: You play chess like a girl! Schniezel: That doesn't really work as an insult. Lelouch: Yeah it sounded so much better in The Sandlot.
0:44 That's not impossible at all. Lelouch is playing black, he is in very favorable position. I'm an amateur chess player and I would put money on the table that I would beat a grand master from that position. Oh and 3:50 that's an illegal move Schneizel made.