Nymphs can attempt to dominate a target with a kiss on a failed Will save (DC 10+1/2 Character Level (+Charisma Bonus for a humanoid target)). A target with at least as many hit dice as the nymph is charmed instead of dominated. This effect lasts for 1d6 rounds per level. Undead, constructs and plants are immune to this effect.
Exact types which can be affected are listed here:
Full DC vs:
Dwarf, Elf, Giant, Gnome, Half Elf, Gray Orc, Halfling, Half Orc, Human, Goblinoid, Orc, Planetouched
Reduced DC vs:
Animal, Beast, Dragon, Fey, Monstrous Humanoids, Reptillians, Outsiders, Yuan-ti, Shapechangers
All others are not valid targets.