North Dakota is around the same size as Nebraska.

Nebraska is approximately 199,099 sq km, while North Dakota is approximately 178,647 sq km, making North Dakota 89.73% the size of Nebraska. Meanwhile, the population of Nebraska is ~1.8 million people (1.2 million fewer people live in North Dakota).
Tip: This to-scale comparison of Nebraska vs. North Dakota uses the Mercator projection, which distorts the size of regions near the poles.