Instead of folding the chocolate chips into the batter, sprinkle them on top of the batter. My method: half batter down in pan, chocolate chips, rest of batter, followed by remaining chocolate chips. Also, use mini chocolate chips and gently toss in flour to coat the chocolate may help. When the cake batter is too thin, sometimes the chocolate chips sink. This cake batter is a perfect consistency so they chocolate chips will remain suspended in the cake.