Caitlyn Jenner 's signing off on her daughter's relationship with Timothée Chalamet ... calling him a good kid and phenomenal actor. The reality star and former Olympian chatted with a photog at LAX ... and, though she didn't dive into deets on her daughter's romance with the A-list actor, she did say she's met Chalamet and calls him a "great kid." CJ says she saw "Marty Supreme" -- adding Chalamet's a very talented actor -- but, more importantly, he's good to Kylie Jenner , which is all