Made this for my sister's family too when I visited her. Her husband hadn't eaten kale before and found he loved it. Even before we had popped it into the oven, he tried a piece of the oiled kale and liked eating it raw. I don't really like kale until it's been cooked but this seems like a great recipe for winning over people who say they don't like kale. Or maybe good for using the kale that keeps showing up in your CSA box.
For my first batch, I forgot the chipotle powder so I used salt and a few squeezes of lime juice and that enough to get us hooked. I remembered chipotle powder for the second batch and that adds good measure of heat to this snack.
The trickiest part is baking them long enough to get everything uniformly crispy but then not so long that it burns. It's a very fine line between almost-done and irredeemably burnt. Seems to be important to keep them in a single layer. It might also be helped by making the pieces more of a consistent size. Is smaller better than bigger? Not sure on that. Apparently you can make the pieces too small. My sister tried using the ready-washed and cut bags of kale at the grocery store and those burned. Maybe she could've used them if she had pulled them out of the oven sooner.