Honestly I doubt the NV would have any trouble at all with Xenos. Lets review a Xenomorph: First the Facehugger latches onto the host, subjecting the host to a temporary comma. The Facehugger then implants an egg down the hosts throat, beneath the rib cage. The Facehugger then dies and the host regains consciousness. The egg grows inside the host for any time period of a few hours to a few days, before it bursts through the hosts chest cavity and enters the world. From there, the Xenomorph rapidly grows into an adult and goes on a killing spree. It's hide is thick, it's teeth and claws as strong as steel, molecular acid for blood, and is a master at stealth. All of these things are formidable... against a normal ass human.
To any ninja in the NV, these things are probably genin-chinin level annoyances. Any good medical ninja could stop the process as early as the chestburster by surgically removing it. Keep in mind, Sakura shoved her hand into Naruto's chest and physically pumped his heart for him. Simply reaching in and removing an alien life form is possible in the NV. You could even make the argument that they could remove the Facehugger from the host as well. But for the sake of argument, lets assume a full grown Xenomorph makes it way into the NV... Just about any basic level Jutsu would be sufficient enough to harm the Xenomorph. Most from a distance as well. Any sensory type ninja of any kind would be able to detect it. And any ninja with fire style jutsu automatically have victory assured.
