Place egg whites in a large bowl; let stand for 30 minutes. Add the vanilla, cream of tartar and salt; beat on medium speed until soft peaks form. Gradually add sugar, 1 tablespoon at a time, beating on high until stiff glossy peaks form and sugar is dissolved, about 6 minutes. Fold in chocolate chips and nuts. , Drop by rounded teaspoonfuls 2 in. apart onto parchment-lined baking sheets. Bake at 250° for 40-45 minutes or until firm to the touch. Turn oven off; leave meringues in oven for 1-1/2 hours. Remove to wire racks. Store in an airtight container.