No, the Earth is not primarily composed of nickel. While nickel is a significant component of the Earth's core, it's not the dominant element.

Here's a breakdown of the Earth's composition:

* Iron: Makes up the largest portion of the Earth's core, accounting for around 88% of its mass.

* Nickel: Is present in the core, but in a much smaller amount than iron, around 5.5%.

* Silicon: The most abundant element in the Earth's crust, making up about 28% of its mass.

* Oxygen: The second most abundant element in the crust, around 47% by mass.

* Other Elements: The remaining elements, including magnesium, aluminum, calcium, sodium, potassium, and others, make up the rest of the Earth's composition.

So, while nickel is a significant element in the Earth's core, it's not the primary component. Iron takes the lead by far.