New Mexico is about 1.2 times bigger than New Zealand.

New Zealand is approximately 268,838 sq km, while New Mexico is approximately 314,310 sq km, making New Mexico 17% larger than New Zealand. Meanwhile, the population of New Zealand is ~5.1 million people (3.0 million fewer people live in New Mexico).
Tip: This to-scale comparison of New Zealand vs. New Mexico uses the Mercator projection, which distorts the size of regions near the poles.