In a shallow bowl, beat the egg white until frothy. In another shallow bowl, whisk together the nut flour, Parmesan, garlic powder, salt, and pepper
Pat the chicken tenders dry. Dip each into the egg white, then dredge in the nut flour mixture. Place on a waxed paper lined plate.
In a large skillet over medium heat, combine 1 ½ tablespoon of olive oil with half a tablespoon butter. Once hot, add half of the tenders and cook until golden brown, about 3 minutes per side. Remove to a plate and repeat with another 1 ½ tablespoons of oil, half a tablespoon of butter, and the remaining chicken tenders.
Add the shallot and garlic to pan and cook until fragrant, about 30 seconds. Add the broth and lemon slices and bring to a simmer. Cook until thickened and reduced by half, another 7 minutes or so.
Add the lemon juice and capers, then add remaining butter in 3 pieces. Stir until melted and smooth. If you want a thicker sauce, whisk in ¼ teaspoon glucomannan or xanthan gum. Season with salt and pepper.
Serve the chicken over lightly steamed zucchini noodles or cauliflower rice. Spoon the sauce over the chicken before serving.
