Nebraska is about 1.3 times smaller than Wyoming.

Wyoming is approximately 251,489 sq km, while Nebraska is approximately 199,099 sq km, making Nebraska 79.17% the size of Wyoming. Meanwhile, the population of Wyoming is ~563,626 people (1.3 million more people live in Nebraska).
Tip: This to-scale comparison of Wyoming vs. Nebraska uses the Mercator projection, which distorts the size of regions near the poles.