In large microwave-safe mixing bowl, stir together cereal and walnuts; set aside.

In a microwave-safe measuring cup, stir together brown sugar, orange juice concentrate and oil and microwave on high 1 minute; stir. Microwave another minute, stirring after 30 seconds, until mixture is hot. Pour over cereal mixture; stir until the cereal mixture is coated.

Microwave the mixture uncovered on high for 5 minutes, stirring every 2 minutes. Stir in cranberries. Spread on waxed paper or foil to cool. Store in tightly covered container.