Heat oven to 350°F. Spray 8-inch round cake pan with cooking spray.
Unroll each can of dough into 1 large rectangle; if using crescent roll dough, press perforations to seal. Cut each rectangle into 8 rows by 3 rows, to make 24 pieces per rectangle (48 pieces of dough total).
Place about 8 chocolate chips in center of dough piece; shape dough into a ball around chocolate. Pinch dough to seal. Repeat with remaining dough and chocolate chips.
In small bowl, mix granulated sugar and cocoa. Roll dough balls in sugar mixture until coated. Place dough balls in cake pan. Sprinkle any remaining sugar mixture over dough. Pour melted butter on top.
Bake 35 to 40 minutes or until no longer doughy in center. Cool in pan 5 minutes. Run knife around edge of pan to loosen. Place heatproof serving plate over pan; carefully turn plate and pan over. Remove pan; immediately scrape any remaining topping from pan onto bread. Sprinkle with powdered sugar. Serve warm.