The following contains spoilers for X-Men Unlimited #32, now available on Marvel Unlimited.
Although the X-Men's nation of Krakoa is dedicated to protecting and supporting mutants, not all mutants agree with this new society. One of the core laws of Krakoa forbids mutants from killing humans. Nature Girl disagrees with this law, and this has made both her and her other allies on the team known as X-Men Green into enemies of Krakoan society.
Nature Girl believes that humans must be held accountable for the atrocities they have commited against the planet, and she has taken it upon herself to murder the humans responsible for harming the environment. She and Curse, a sadistic young mutant with a tendency toward violence, were tried by the Quiet Council and exiled to the Pit as punishment for breaking the law. However, Krakoa itself disagreed with this ruling and secretly helped smuggle them off the island. Krakoa also gifted Nature Girl with a magical staff to aid her on her mission. Now, the X-Men Green team of Nature Girl, Curse, Saoirse the German shepherd, and the mutant Sauron continue their eco-terrorist actions in an effort to protect the planet.
X-Men Green is not the only team of eco-terrorists whom the X-Men have deemed their enemies. Soon after the nation of Krakoa was established, the X-Men encountered a group of elderly women stealing medicinal plants from their island. This turned out to be Hordeculture, a group of scientists who planned to wipe out a large contigent of the human population in the hopes of restoring the environment. Hordeculture's expert knowledge of botany and ruthless determination to cull mankind made this team a legitimate threat to both the X-Men and the world.
In X-Men Unlimited #32 (by Karla Pacheco, Emilio Laiso, Rachelle Rosenberg and VC's Joe Sabino), X-Men Green escapes from a fight by traveling through a Krakoan portal that transports them to Hordeculture's base. The women of Hordeculture help heal the team from the fight and reunite Nature Girl with the Krakoan staff that she had lost previously. Even though Hordeculture has been established as an enemy of the X-Men, Nature Girl doesn't regard the group as antagonists because she knows that the living island Krakoa doesn't feel threatened by them. Krakoa sent Hordeculture Nature Girl's staff to return to her and intentionally sent X-Men Green to the base of the eco-terrorists when they went through the portal. The living island appears to have wanted the two teams to meet.
Since X-Men Green and Hordeculture both care so strongly about the environment and are willing to commit murder in its defense, it would make sense for them to work together. In their first meeting, the two teams appear friendly towards one another. Both sides could benefit from an alliance, as they can each offer something the other lacks.
However, there is also the possibility that Hordeculture intends to manipulate X-Men Green for its own ends. Augusta, the apparent leader of Hordeculture, seems to indicate this much when she explains to another member that they will be able to use Nature Girl. Whether X-Men Green and Hordeculture choose to form a more permanent alliance or decide to continue operating separately, they both are sure to remain a thorn in the X-Men's side for the foreseeable future.