Preheat oven to 325 degrees F. Spray a 15- x 10- x 1-inch jellyroll pan with cooking spray. Line with waxed paper or parchment paper and spray again; set aside.
Sift cocoa, flour and salt into a small bowl; set aside. In medium bowl, beat egg whites with electric mixer at high speed until frothy; beat in cream of tartar at high speed. Continue to beat until stiff peaks form when batter is lifted with rubber spatula.
Using the same beaters, in another medium bowl, beat yolks at medium speed until thick and lemon colored, 2 to 3 minutes. Gradually beat in 1/3 cup of sifted powdered sugar and 1 teaspoon of vanilla at medium speed; scrape bowl.
Use a rubber spatula to stir in cocoa mixture. Using the rubber spatula, gently fold beaten whites, half at a time, into yolk mixture until no white streaks remain.
Spoon into prepared pan and smooth with rubber spatula. Bake 12 to 15 minutes or until center springs back when lightly pressed.
Meanwhile, in medium bowl, beat ricotta until smooth with electric mixer at low speed. Use a rubber spatula to stir in toasted nuts, rum, sugar, orange peel, chips and remaining 1/2 teaspoon of vanilla until well blended.
Lay a clean dishtowel on counter and sprinkle with remaining sifted confectioners' sugar.
Remove cake from oven and loosen edges with knife. Place cake side down on prepared towel; lift off baking pan and peel off paper. Starting at short end, roll up cake and towel. Place seam side down on rack to cool about 15 minutes.
Unroll cake and spread filling to within 1/2-inch of edges. Using towel as a guide, reroll cake with filling. Place seam side down on serving plate; cover. Refrigerate at least one hour or up to 4 hours before serving. Sprinkle cake with sifted confectioners' sugar before serving.