You surmise correctly.

Psions are good at going nova because many of their powers can be augmented. Whereas spellcasters have most aspects of their spells scale with level up to a certain point, typically psionic powers only automatically scale with respect to duration and range. To get more out of a power, a manifester has to augment the power: spend extra power points.

This augmentation also comes with the benefit of no absolute caps beyond the psionic character's manifester level. Whereas a wizard's fireball can never do more than 10d6 damage on its own regardless of the wizard's caster level, a 20th level kineticist can unleash a 20d6 energy ball. Due to this expanding power level, a fully augmented psionic power can be more powerful than a spell of the same level, though it should be noted such powers require the psionic energy of a much higher level power. For instance, that energy ball is a fourth level power, but it cost more power points than a 10th level power.

This augmentation allows a psion to go nova using virtually any of his or her known powers, whereas a wizard would only find a few of his or her highest level appropriate for such a task.