HEAT oven to 350°F.
LINE 2 (9-inch) round pans with parchment; spray with cooking spray. Microwave butter and 3/4 cup sugar in microwaveable bowl on HIGH 2 min.; stir until blended. Pour into prepared pans; tilt pans to evenly cover bottoms. Reserve 1 Tbsp. nuts; sprinkle remaining nuts over butter mixture in pans. Beat cake mix, pumpkin, water, oil and eggs in large bowl with mixer until blended; pour over nuts in pans.
BAKE 26 to 28 min. or until toothpick inserted in centers comes out clean. Cool cakes in pans 10 min. Loosen cakes from sides of pans with knife. Invert cakes onto wire racks; gently remove pans and parchment. Cool cakes completely.
BEAT cream cheese, milk and remaining sugar in medium bowl with mixer until blended. Gently stir in COOL WHIP.
STACK cake layers, praline sides up, on serving plate, spreading half the cream cheese mixture between layers. Spread remaining cream cheese mixture onto top of cake; sprinkle with reserved nuts.