FOR COFFEE CREAM SAUCE: BEAT egg yolk in small bowl. Set aside.
COMBINE sweetened condensed milk, water, coffee granules and cornstarch in medium saucepan. Cook over medium heat, stirring constantly, until mixture is hot. Gradually stir about 1 cup hot mixture into beaten egg yolk. Stir egg mixture back into mixture in saucepan. Cook until sauce comes to a full boil and thickens. Remove from heat. Stir in vanilla extract.
FOR CHIMICHANGAS: COMBINE bananas, nuts and 3/4 cup Coffee Cream Sauce in medium bowl. Spoon about 1/3 cup mixture down center of each tortilla. Fold bottom sides up and roll up. Secure with wooden picks.
POUR oil into large skillet to about 1-inch depth. Heat over medium heat. Fry 2 to 3 chimichangas at a time, turning frequently, for about 2 minutes or until golden brown. Drain on paper towels. Remove wooden picks. Serve warm with remaining Coffee Cream Sauce.
COFFEE CREAM SAUCE
1 large egg yolk
1 can (14 ounces) NESTLÉ LA LECHERA Sweetened Condensed Milk
2/3 cup water
2 1/2 teaspoons NESCAFÉ CLÁSICO Pure Instant Coffee Granules