Hi there and thank you for your question!
There is no major nutritional difference between curly and dinosaur or 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.1 For example, baked kale chips can contain more nutrition than kale that is boiled for a long time.
All varieties of kale are packed with nutrition: from vitamin C and calcium, to fiber and antioxidants. Regardless of the type of kale you choose, adding kale along with a variety of other vegetables and fruits in your meal can be very beneficial for your health.2
Hope this helps!
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
Robinson, Jo. Eating on the Wild Side: The Missing Link to Optimum Health. 2013. Little, Brown and Company: New York, NY.