Small problem, big actions
To exaggerate the size of a problem
Negative
近年来，当学生在学校被要求做一些家务时，一些家长就会小题大做 | Jìnnián lái, dàng xuéshēng zài xuéxiào bèi yāoqiú zuò yīxiē jiāwù shí, yīxiē jiāzhǎng jiù huì xiǎotídàzuò
In recent years, when students have been asked to do chores at school, some parents will make an unnecessary fuss
[Source]
这些人就是喜欢小题大做 | Zhè xiē rén jiù shì xǐhuān xiǎotídàzuò
These kinds of people just like to make mountains out of molehills
[Source]
To make a mountain out of a molehill
小题大作 (xiǎo tí dà zuò)
So apparently 小题大作 is a variation of this chengyu, but at least one dictionary I consulted told me to NOT use 小题大作, so take the variation with a grain of salt
《战国策》(Zhàn Gúo Cè, Strategies of the Warring States), a work which chronicled the Warring States Period (475 - 220 BC)
During the Warring States Period (战国时期 | zhàn guó shí qī | 475 - 221 BC), the kingdom of 燕国 (Yān Guó) invaded the neighboring kingdom of 赵国 (Zhào Guó). The king of 赵国, 孝成王 (Xiào Chéng Wáng), was apparently convinced that none of his own generals would be able to repel the invaders, so he asked the country of 齐国 (Qí Guó) to send its general 田单 (Tián Dān) to lead 赵国's defense efforts. The king of 齐国 agreed — provided that 孝成王 hand over three cities and fifty-seven towns in return.
When the famous 赵国 general 赵奢 (Zhào Shē) heard that 孝成王 was earnestly considering the 齐国 monarch's terms, he grew furious, and he swiftly complained to the lord 赵胜 (Zhào Shèng): "赵国 has men capable of fighting of 燕国, does it not? The land that we are ceding to 齐国 was gained after many violent battles, and now we're handing it over in exchange for a general? I am very familiar with 燕国. Why don't you let me go and fight their forces?!"
赵胜 replied, "I have spoken to the king, and he's already agreed to 齐国's terms. What's done is done."
赵奢 shot back, "No, it's not done. Don't you see what will happen here, [that our originally small problem has just become much bigger]? Why would 齐国 want to aid 赵国? It's because they're going to use our troops, our provisions, our resources, everything that we have, to fight against 燕国. In the end, both 燕国 and 赵国 will be exhausted, and 齐国 will come out on top because they haven't lifted a finger. How can you not understand this?!"
Unfortunately, in the end, 赵奢's predictions were accurate.