Combine walnut, spice powder, sesame, and brown sugar in small bowl and toss to coat
Heat skillet on medium for 3 minutes
Add walnut mixture and stir constantly until sugar melts and coats walnuts (about 1 1/2 minutes)
Quickly spread coated walnuts evenly on foil sheet
Break apart when cool
Scoop 1/2 cup ice cream in dish and top with 1/4 cup sliced mango and 1 1/2 tbsp coated walnuts