2 cups boiling water
1 cup white sugar
1 (2 ounce) jar instant coffee granules (such as Nescafe®)
1 gallon 2% milk
1/2 gallon vanilla ice cream
1/2 gallon chocolate ice cream
Stir boiling water, sugar, and instant coffee together in a bowl until dissolved; cool in refrigerator, 30 minutes to overnight.
Pour coffee mixture into a punch bowl; add milk, vanilla ice cream, and chocolate ice cream. Stir until ice cream begins to melt.