That's great you've got a nice chinchilla. I have had mine get loose many times and have been able to track him down every time so don't panic if she gets down but certainly don't hesitate to capture her. Sometimes my chinchilla gets in a mood where he just wants to jump away and run around while most of the time he's usually pretty calm. When I think it's likely he'll get loose I close the door to my room. You can try to get her to come but a curious chinchilla is not easily distracted.
Another thing I have found helpful is a net. I have a a fine mesh net about 12" in diameter on a wooden pole that is very lightweight. I rarely get the animal into the net but it's fairly safe to use it to chase him out from under furniture. A broom might work but is much heavier and can cause some damage if you are not careful.
Keep in mind that the safest way to handle a chinchilla is to hold it firmly by the base of the tail and support it under the chest at the same time. It looks strange and horrifying to do this and sometimes the animal does struggle but it does not cause injury or discomfort to the animal to pick it up by the base of the tail. If she struggles in your hands don't immediately let go but let her go the moment she becomes still. (Chinchillas usually struggle in short bursts)
Do not try to catch it by the tail or hold it further down our you can break the tail. Also support under the front legs. Avoid squeezing around the ribs too hard because they need to be able to breathe but hold her around the chest securely. Secure is safe. Loose is dangerous especially is she starts flailing around when she's partially restrained. This is known to cause serious injury.
Do not hold around the abdomen where the intestines are. I know there are people who say they have a "floating rib cage" and that will dislocate ribs but that is not true. Their ribs are fragile but they are also flexible. I have never injured my chinchilla by holding it under the chest.
Sometimes when a chinchilla is struggling it's easy to grab a leg by mistake especially if you have to chase her. Avoid grabbing feet or legs as this can easily cause a dislocations and all kinds of problems especially if the animal kicks and flails. Once the chinchilla is out of the cage you may not be able to hold her for very long (like 20 seconds) until she starts getting very upset and slipping fur so be prepared. I've been bit training my chinchillas to tolerate being held so be careful. Try not to over-react and re-enforce negative behaviors. A chinchilla that is not used to be held will take some time but the more often you do it the longer the animal will tolerate being held. Try to put her back down before it gets bad. Be deliberate and consistent in the way you do things and you'll be successful. I have been very successful with two chins, the first one being pretty wild. You'll get there.