Err, the Enterprise has been a ship name for a few hundred years, quite a bit before Star Trek was ever conceived.
Amusing that the page for ships called HMS Enterprise linked to from the USS Enterprise page points out that the name came originally from the French!
Nostromo could be a reference to Joseph Contrad's novel. Its also an italian word for boatswain (according to Wikipedia)
There's a fun time loop here: The Star Trek Enterprise and the real-life space shuttle Enterprise were each named after the other. In real life, the shuttle was named after the Star Trek ship. In-universe, the first starship Enterprise (NX-01) was named after the space shuttle. [Edit: I remember reading that years ago, but can't find any official source saying so now, although the intro to the Star Trek Enterprise tv series does emphasize the shuttle.]
(Of course, both really come from a long lineage of naval vessels with the name.)