Nova is a skill located in the Dawn's Wrath (which can be found in the Templar skill tree). Nova is an ultimate. Nova is a base skill, and can be morphed into Solar Prison or Solar Disturbance.
Nova deals the following types of damage: Magic Damage. Which means that it gets buffed by the following blue champion point trees: Elemental Expert, Elf Born, Master at Arms, Spell Erosion. Also the following red champion point trees protect against this skill: Elemental Defender, Iron Clad.