Brunei is about 55 times smaller than New Mexico.

New Mexico is approximately 314,310 sq km, while Brunei is approximately 5,765 sq km, making Brunei 1.83% the size of New Mexico. Meanwhile, the population of New Mexico is ~2.1 million people (1.6 million fewer people live in Brunei).
Tip: This to-scale comparison of New Mexico vs. Brunei uses the Mercator projection, which distorts the size of regions near the poles.