Nativity is a fancy way to say "birth." If you were born in Baltimore, you can say that's the location of your nativity.
Being born is a person's nativity, but the noun is most frequently used when Christians talk specifically about the birth of Jesus Christ. If a new mother says, "My baby's nativity was beautiful!" people might not know what she means. Nativity comes from the French word nativité, which also means "birth." The Latin root word is nativus, "born or native."