Congrats on the acquisition of your baby Rhino. Rhino iguanas do well on a diet similar to that of Green Iguanas. The primary diet should consist of dark leafy greens such as Collard, Mustard, Turnip, and Dandelion. Vegetables well suited to Cyclura are winter squash, parsnip, green beans, snap peas, sweet potato, and okra. Fruit should make up less than 10% of the diet. Good fruits include figs, papaya, mango, berries, melons, and grapes. I also add some grains to my Cyclura's diet, including whole wheat bread, plain cooked pasta, and wild rice.
I hope this helps. Here is a link to a good site about Green Iguana diets.
GIS food chart