I assume you are taking an additional subject that you did not mention? This is because you cannot take Chinese Beginners alongside the other subjects that you mentioned as this combination would amount to 11 units instead of the required 12 units for year 11.
Regardless, Chinese Beginners seems like a more comfortable alternative to English Extension 1. Not only is it likely to impose a lighter workload than that of English Extension 1, but it could also be easier given that it is a Beginners language course, especially if you have previous exposure to the Chinese language. While taking Chinese Beginners through NSL will require you to be committed and diligent, favourable performance is definitely possible, which leads to the suggestion that the option of keeping this subject going into year 12 would likely mean a reasonable workload and favourable performance across your subjects.
On the other hand, a perceived advantage of taking English Extension 1 is that it can assist you in developing your writing abilities, which, in your case, could be useful in terms of English Advanced after you drop English Extension 1. I believe it would be safe to suggest that History Extension will be more demeanding than Chinese Beginners. Based on this, unless you feel more interested in English Extension 1/History Extension than Chinese Beginners, you should consider the impact of choosing the former on the nature of your workload and your ability to manage it.
I hope this helps!