Hi there and thank you for your question!
Great news - all varieties of kale are packed with nutrition: from vitamin C and calcium, to fiber and antioxidants. Including kale (along with a variety of fruits and vegetables) in your diet can protect your heart and help reduce your risk of cancer regardless of the kale type!1
There is no major nutritional difference between curly and dinosaur/lacinato kale, but the way it is cooked and prepared can change the nutritional value. Different cooking methods, such as steaming, baking, or sauteéing, can help retain more nutrients in food than other methods.2 For example, baked kale chips contain more nutrition than kale that is boiled for a long time in a stew.
Hope this helps!
Robinson, Jo. Eating on the Wild Side: The Missing Link to Optimum Health. 2013. Little, Brown and Company: New York, NY.
Lee, Seongeung et al. “Effect of different cooking methods on the content of vitamins and true retention in selected vegetables.” Food science and biotechnology vol. 27,2 333-342. 12 Dec. 2017, doi:10.1007/s10068-017-0281-1