How to Make It
Preheat oven to 325°F and line 2 baking sheets with parchment paper. Place hazelnuts, salt, and ¼ cup of the sugar in the bowl of a food processor; pulse until mostly finely ground but with a few large pieces of nuts still visible, 4 to 5 times.
Beat egg whites and cream of tartar in a large bowl with an electric mixer on medium-high speed until soft peaks form, 2 to 3 minutes. Reduce speed to medium, and gradually add remaining ¾ cup sugar, 1 tablespoon at a time, beating well after each addition. Increase speed to high, and beat until stiff peaks form, about 1 minute. Beat in vanilla.
Sprinkle hazelnut mixture over top of egg whites and gently fold until mixture still has a few white streaks remaining. Sprinkle chocolate chips over batter and gently fold in until mixture is evenly combined. Drop 2 tablespoonfuls of meringue 2 inches apart on prepared baking sheets.
Bake until lightly browned and set, 18 to 20 minutes. Let cool on sheets about 5 minutes. Transfer cookies to wire racks to cool completely, about 20 minutes.