Drain orange sections, reserving syrup. Add enough water to syrup to measure 1 cup liquid. In a saucepan, bring syrup mixture to boiling. Add gelatin, stirring to dissolve. Stir in orange juice. Gradually stir about 1 cup of the hot mixture into eggs; return all to saucepan. Cook and stir 2 minutes more. Remove from heat. Add sour cream and cream cheese; beat with a rotary beater until smooth. Chill until partially set (the consistency of unbeaten egg whites). Fold in orange sections, sliced banana and nuts. Turn into a 10 x 6 x 2 inch dish. Chill until firm. Cut into squares. Serve on lettuce-lined salad plates. Makes 8 servings.