Niger is about 4 times bigger than New Mexico.

New Mexico is approximately 314,310 sq km, while Niger is approximately 1,267,000 sq km, making Niger 303% larger than New Mexico. Meanwhile, the population of New Mexico is ~2.1 million people (22.4 million more people live in Niger).
Tip: This to-scale comparison of New Mexico vs. Niger uses the Mercator projection, which distorts the size of regions near the poles.