Oman is around the same size as Nevada.

Nevada is approximately 284,448 sq km, while Oman is approximately 309,500 sq km, making Oman 9% larger than Nevada. Meanwhile, the population of Nevada is ~2.7 million people (1.1 million more people live in Oman).
Tip: This to-scale comparison of Nevada vs. Oman uses the Mercator projection, which distorts the size of regions near the poles.