Combine 6 Tbsp. sugar and 2 Tbsp. cornstarch in a medium saucepan over medium heat.
Combine milk and egg, stirring well with a whisk.
Gradually add milk mixture to sugar mixture, stirring constantly, and bring to a boil.
Cook for 1 minute, stirring constantly.
Remove from heat.
Combine pumpkin and the next 4 ingredients (through ground nutmeg) in a bowl, stirring well.
Slowly add pumpkin mixture to milk mixture, whisking constantly.
Place pan over low heat, and cook for 3 minutes or until thoroughly heated, stirring constantly (do not boil).
Divide pudding evenly among 4 dessert bowls, and cover surface of pudding with plastic wrap.
Chill.
Line a baking sheet with foil, and coat foil with cooking spray.
Place the remaining 2 Tbsp. sugar, walnuts, and a dash of salt in a small nonstick skillet; cook over low heat until sugar dissolves and is golden (about 3 minutes), stirring frequently to coat nuts.
Transfer mixture to prepared baking sheet, and cool completely.
Coarsely chop nuts.
Place cream in a bowl.
Beat with a mixer at high speed until stiff peaks form.
Top each serving with 2 Tbsp. whipped cream and about 1 Tbsp. nuts.