Why is nucleus called the director of the cell?

The nucleus is called the "director" of the cell because it controls the cell's activities. The nucleus is the is organelle that directs all of the other functions of the cell. DNA, the genetic material of an organism, is located in the nucleus. DNA is made of amino acids, which combine to form proteins. Proteins then act to direct specific functions including acting as enzymes to drive chemical reactions. This entire process begins in the nucleus of the cell, making it the cell's director.

The nucleus is sometimes referred to as the "director" of a cell because it controls the functions of the cell. Just as a director of a play or movie controls what happens in the show, the nucleus "directs" the cell by regulating the genes the cell contains.
The nucleus is a membrane-protected organelle found in eukaryotic cells (those found in plants and animals). It contains many important things like DNA and RNA and helps the cell to do important activities like move, absorb nutrients, create proteins, and create new cells. The nucleus is made up of multiple different parts that all work together to help it function. It holds the instructions for the rest of the cell's parts to do their jobs correctly. Because it is in charge of helping the cell function in this way, the nucleus is called the "director" of the cell.

The nucleus can be thought of as the "director" of the cell because it directs all the activities of the cell. It is sometimes also called the brain of the cell.
The nucleus is a membrane-enclosed organelle of a cell and is found in eukaryotic cells (for example, plant cell, animal cell, etc.). It stores the DNA of the cell which can be thought of as the code for building proteins, which in turn regulates all the activities of the cell. Through regulation of the protein synthesis, the nucleus is able to direct cell activities, such as metabolism, growth, reproduction, etc.
This ability of the nucleus to control the activities of the cell is the reason it is known as the director or brain of the cell.
Hope this helps.