Heat oven to 375°F.
Beat first 4 ingredients in large bowl with whisk 2 min. (Mixture will be thick.) Stir in Cool Whip. Refrigerate until ready to use.
Meanwhile, place won ton wrappers on parchment-covered baking sheets; brush with butter. Combine cinnamon and sugar substitute; sprinkle over won tons. Bake 6 to 8 min. or until golden brown. Remove to wire racks; cool completely.
Top each of 12 won tons with about 2 Tbsp. pumpkin mixture. Repeat layers twice. Drizzle with syrup just before serving; sprinkle with nuts.
How to Toast Nuts: Toasting nuts adds crunch and intensifies their flavor. To toast nuts in the oven, spread nuts in single layer in shallow baking pan. Bake at 350°F for 8 to 10 min. or until golden brown, stirring occasionally. To toast nuts on the stovetop, place nuts in ungreased skillet. Cook on medium heat until golden brown, stirring frequently. To toast nuts in the microwave, place up to 1 cup of nuts in a microwaveable shallow dish. Microwave on high until fragrant and crisp, stirring every 30 sec.
How to Store: Refrigerate any leftovers.
Nutrition Bonus: Rich in vitamin A, the canned pumpkin adds the perfect touch of flavor to this stunning layered dessert.