IMO this is more likely due to the moment you decide to play the chiquita rather than your technique:
1. Only play chiquitas on easy balls (same as for the lob)
2. Chiquitas only work when there's space between the opponent and the net, if they are close to the net you are effectively handing them the point. A good tactic would be to first play a couple of lobs to force them back and if they don't come back to the net properly you've created a gap in front of them to play into. Some players will stand too close to the net the whole match so then you simply play no chiquitas and easily pass them with lobs all the time and say thank you very much
3. The chiquita is a soft shot by nature. The further you are at the back of the court when you play it, the longer the ball travels to the net and the more time the opponent has to come in and volley. So ideally you play a chiquita when you are closer to the net (around the service line or even closer) for example when the opponent plays a short, easy ball. Even better are balls that come off the glass far enough, because then your are closer to the net AND you're already running forwards to attack the next ball if the opponent lifts the ball up too much after your chiquita
4. This is an advanced tip but the best chiquitas are the ones where the opponent thinks you are going to play a lob and already takes a step back, which again means you have a lot of space to play in so the chiquita itself does not have to be perfect. In order to do this however, you will need to be able to play both a lob or a chiquita with the same racket preparation (open racket face, small backswing, close to the body). A popular drill coaches use for this is playing balls and shouting for example "High" or "Low" just before you are hitting the ball. Watch the pros play and you will notice how amazing they are at hiding which shot they're going to make.
