In a small baking dish, stir together pecans, breadcrumbs, rosemary, coconut palm sugar, salt and cayenne pepper. Add the olive oil and toss to coat the pecan mixture.
Bake until the pecan mixture is light golden brown, 7 to 8 minutes.
Increase the heat to 400 degrees F. Coat a large glass baking dish with cooking spray.
In a shallow dish, whisk the egg white. Working with one tilapia at a time, dip the fish in the egg white and then the pecan mixture, lightly coating each side. Place the fillets in the prepared baking dish.
Press the remaining pecan mixture into the top of the tilapia fillets.
Bake until the tilapia is just cooked through, about 10 minutes. Serve.