How can nuclei accommodateall of our genetic material
(3,000,000,000 base pairs)?

By forming chromatin and in the condensed form of chromosomes

Explanation:

The human genome contains around 3 billion base pairs which are located in the nucleus of all cells. In order to accomodate such large genomic information, DNA is maximally supercoiled during mitosis and meiosis processes to form condensed structures called chromosomes. Humans have 23 pairs of chromosomes per somatic cell. The supercoiling process is assisted by a family of proteins called histones, which interact with DNA and regulate its conformation. The complex between DNA and histones within the nucleus is called chromatin. When chromatin is supercoiled it form chromosomes (in eukaryotic cells).