Hope she is not sleeping in an aircon room as it will aggravate her stuffy nose. If you have a humidifier or vaporiser, you can use it as water vapour can help moisten the mucus. You can buy Sterimar Nasal spray from the pharmacy to help loosen the mucus and use a nasal aspirator or nose cleaner to suck out the mucus. I would recommend Lollababy Nasal Aspirator or Pigeon nose cleaner. But if she has difficulty breathing or wheezing, trouble feeding, do see a paediatrician asap.