Monaco is about 157,155 times smaller than New Mexico.

New Mexico is approximately 314,310 sq km, while Monaco is approximately 2 sq km, making Monaco 0.0% the size of New Mexico. Meanwhile, the population of New Mexico is ~2.1 million people (2.0 million fewer people live in Monaco).
Tip: This to-scale comparison of New Mexico vs. Monaco uses the Mercator projection, which distorts the size of regions near the poles.