Creatures you control with counters on them have trample.
Whenever you cast your first spell with {X} in its mana cost each turn, put X +1/+1 counters on Nev.
If you cast your first spell with {X} in its mana cost during a turn before Nev is on the battlefield, casting another spell with {X} in its mana cost later in the turn won't cause his last ability to trigger.