HEAT oven to 400ºF.
COMBINE nuts, cinnamon and 1 pkt. sweetener. Place 1 phyllo sheet on work surface; brush with 1/3 of the margarine, then sprinkle with 1/3 of the nut mixture. Repeat layers twice; place in 9-inch tart pan. Fold over edges of pastry to form 1-inch-high rim around edge of pan.
MIX cream cheese spread and remaining sweetener until well blended; spread onto bottom of crust. Arrange plums in circular pattern over cream cheese mixture.
BAKE 20 min. or until pastry is golden brown. Sift sugar over tart. Serve warm or at room temperature.