The chi-square test is a continuous probability law and at the same time is a nonparametric test which compares qualitative data with the use of small samples in the sub-groups but not in the total number.
In the literature of the various books and statistical courses to make a chi-square, the total number with the different groups must be greater than 30 sufficient to give a statistical conclusion
If it is a number that is proven as a sampling limit why some require a larger sample?