In a medium saucepan, bring the water, sugar and lemon juice to a boil. Pour into a 9x13 inch dish with the lime flavored gelatin mix, allowing mix to dissolve. Stir in pineapple. Chill in the refrigerator 30 minutes, or until mixture begins to gel.
Stir the Colby longhorn cheese, nuts and frozen whipped topping into the mixture. Chill in the refrigerator 3 to 4 hours, or until firm.