Using a melon baller, scoop the gelato into 48 (1-inch) balls. Transfer the balls of gelato to a small tray and keep the gelato in the freezer until ready to serve.
When ready to serve, cut the ladyfingers in half lengthwise. Spread the nutella on both sides of the split ladyfingers. Place 3 scoops of gelato on the bottom half of the ladyfinger. Top with slices of strawberry and mint leaves. Place the top ladyfinger over to make a sandwich. Repeat with remaining ingredients. Serve immediately.