Beat egg whites and salt at medium speed of a mixer until foamy. Add cream of tartar; beat until soft peaks form. Gradually add sugar, 2 tablespoons at a time, beating at medium-high speed until stiff peaks form. Add vanilla; beat well. Fold in pine nuts and chocolate.
Cover a baking sheet with parchment paper. Spoon egg white mixture into 16 mounds on prepared baking sheet. Bake at 250° for 1 hour or until dry to touch. (Meringues are done when the surface is dry and can be removed from paper without sticking to fingers.) Turn oven off, and partially open oven door; leave meringues in oven 30 minutes. Remove from oven; carefully remove meringues from paper. Store meringues in an airtight container up to 3 days.