Complex sentence: Director Tetsuya Nomura had been given the freedom to choose which characters and worlds he would like to use in the games by Disney, however he and his staff decided to stay within the established roles of the characters and their worlds.
Split into simpler sentences: Director Tetsuya Nomura had been given the freedom to choose which characters and worlds he would like to use in the games by Disney. However, he and his staff decided to stay within the established roles of the characters and their worlds.