North Dakota is about 1.5 times smaller than New Zealand.

New Zealand is approximately 268,838 sq km, while North Dakota is approximately 178,647 sq km, making North Dakota 66.45% the size of New Zealand. Meanwhile, the population of New Zealand is ~5.1 million people (4.4 million fewer people live in North Dakota).
Tip: This to-scale comparison of New Zealand vs. North Dakota uses the Mercator projection, which distorts the size of regions near the poles.