Nevada is about 1.4 times bigger than South Dakota.

South Dakota is approximately 196,540 sq km, while Nevada is approximately 284,448 sq km, making Nevada 45% larger than South Dakota. Meanwhile, the population of South Dakota is ~814,180 people (1.9 million more people live in Nevada).
Tip: This to-scale comparison of South Dakota vs. Nevada uses the Mercator projection, which distorts the size of regions near the poles.