Pour Chex into a large bowl. In a small bowl, melt white chocolate chips in the microwave in 30 seconds intervals. When melted, add shortening to thin. Pour white chocolate over Chex and toss to coat. Once coated, pour powdered sugar and jello over chex and stir until well coated. Squeeze the juice of half of a lemon over mixutre, then toss once again. Pour mixture on wax paper until dry. Enjoy!