Melt the butter with milk in a microwave-safe bowl for 90 seconds or until the butter is fully melted. Stir to combine.
Whisk the vanilla into the milk and butter mixture. In a separate large bowl, beat the eggs until fluffy, then blend in the milk mixture.
Combine the flour, baking powder, salt, and sugar in the egg mixture, stir until just mixed. Allow the batter to rest for 5 minutes (secret to fluffier waffles).
Preheat the waffle iron. Fold the chocolate chips into the batter, then cook the waffles until golden and crisp.