In 2399, the location of Nausicaa was labeled on a star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. The planet was located in or near to Federation space. (PIC: "Maps and Legends")
In the first draft script of "Fortunate Son", Admiral Forrest notified Captain Archer that Starfleet had filed a complaint with Nausicaa, regarding Nausicaan pirates operating in a particular sector of space, but that the Nausicaan government was, according to the Vulcans, in a constant mode of "transition."
According to Star Trek: Star Charts (pp. 60 & 64), Nausicaa was located in the Nausicaa system. This system was a binary star system. Primary star was a Class M star with a magnitude of +3, which was ten times brighter than Sol. Secondary was a Class A star. In the mid-22nd century, this system was in non-aligned space. In 2378, this system was located in or near to Federation space.