HEAT oven to 350ºF.
MIX sugar and butter in medium bowl; stir in pineapple and nuts. Place cherry half, cut-side up, in center of each of 24 paper-lined muffin cups. Cover with pineapple mixture.
ADD boiling water to gelatin mix; stir 2 min. until completely dissolved. Cool 10 min.
BEAT remaining ingredients in large bowl with mixer until well blended. Add gelatin; mix well. Spoon over pineapple mixture in muffin cups. (Cups will almost be completely filled.)
BAKE 15 to 18 min. or until toothpick inserted in centers comes out clean. Cool in pans 10 min.; remove from pans to wire racks. Cool completely. Invert onto plates just before serving; remove paper liners.