In a diploid organism with a haploid chromosome number of 8, there are 16 chromatids present in its metaphase II nucleus. This is because during meiosis, each chromosome replicates to form two sister chromatids, resulting in the doubling of the chromosome number. Therefore, with 8 chromosomes in the haploid set, there are a total of 16 sister chromatids present in the meiotic metaphase II nucleus.
