The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
When the Insect enters the battlefield, Warleader's Call triggers, dealing 1 damage to each opponent.
Niv-Mizzet triggers, causing you to draw a number of cards equal to the damage dealt.
Repeat from step 2.
This beautiful loop turns a single card draw into an unstoppable cascade of damage, tokens, and cards by locking Niv-Mizzet, Visionary and The Locust God into a self-sustaining cycle. Whenever you draw, The Locust God dutifully spawns an Insect token, whose arrival triggers Warleader's Call to ping your opponent for 1 damage. That noncombat damage immediately rouses Niv-Mizzet, Visionary to draw you a card, restarting the entire chain while Warleader's Call's static buff pumps your swarming army for the finish.