Heat oven to 300°F. Line 13x9-inch pan with 18x18-inch square of heavy-duty foil so foil extends over long sides of pan. Spray foil with cooking spray. In small bowl, mix cookie crumbs and butter. Press in bottom of pan.
In large bowl, beat cream cheese and sugar with electric mixer on medium speed 1 to 2 minutes or until smooth. Beat in flour, eggnog and eggs on medium speed until smooth, scraping sides of bowl if necessary. With rubber spatula, fold in chocolate chips. Pour filling evenly over crust.
Bake 35 to 40 minutes or until edges are set. Center will be soft but will set when cool. Cool 1 hour. Refrigerate at least 2 hours. Sprinkle evenly with nutmeg. For squares, cut into 8 rows by 6 rows. Remove from foil. Store squares in refrigerator.