I believe, we say "nothing much" when we want to emphasize that smth is not interesting, important (in negative expressions) For ex., There's nothing much we can do to improve the situation. The expression "nothing more" is more likely to be used as "no more" meaning that smth will no longer happen: No more silly arguments - we'd better go home and calm down. Also, "no more" can be used in expressions like "It's no more than you deserve" (meaning it's exactly what you deserve).

elaborate vividly, thanks 长颈鹿！

Hi, Tala. Kate is correct, 长颈鹿也对不过回答太长. There is nothing much ("not much" is better) we can do about this. (You haven't tried to do anything about this.) There is nothing more we can do about this. (You have already made some effort and failed.)

Tala, 你好！：））） "nothing more" means the same thing as "nothing else." It is also often used when giving a blunt, (and often negative) opinion about something. There is also a common English saying: "nothing more, nothing less." This saying means the same thing as "nothing more," it just adds further emphasis. "nothing much" can be used as a reply to a typical question like, "what are you up to?" or "what's up?". For example, if somebody asks you "what's up," or "what are you doing?" or "What have you been up to lately?", and you don't have anything special going on, you can reply with "nothing much." Such as: Giraffe: "Hey Tala, what are you up to?" Tala: "Nothing much, just studying English, as usual." Here are some examples of how to use "nothing more" when giving a blunt, (and usually negative) opinion: "Your brother is nothing more than a lazy bum!" "The food at that restaurant is nothing more than crap!" "He is a decent cook, nothing more." Here are some examples of how to use "nothing more, nothing less": "Your brother is a lazy bum, nothing more, nothing less." "The food at that restaurant is crap, nothing more, nothing less." "He is a decent cook, nothing more, nothing less." Best wishes! :))))))))))))))))))))))))))))))))))))))