Congrats on your first chin!
Healthiest treats are safe wood and safe herbs. Herbs are rich in nutrients. My chins especially love the
Broad Spectrum Supplement. Herbs are not only sources of fiber, protein, vitamins, minerals, enzymes; they also contain secondary elements that possess medicinal properties. In reality, nutrients from herbs do not just keep herbivores alive; they also keep them healthy. That's why in the wild nutritional equals medicinal. Wild chinchillas consume various herbs. "According to Jiménez (1990), wild chinchillas feed on up to 24 plant species, mainly herbs."
http://www.chinquest.co.uk/JEJSeasonalFoodHabits2002.pdf
You can also offer various hays. Variety encourages chins to eat more hay. Hay is very important for dental health, and long strands of loose hay insure a superior digestive health.