Peel the yucca and cut into 3-inch batons, then boil in salted water for 10 minutes until slightly tender.
Drain the yucca and pat dry; toss with half the avocado oil and a pinch of salt.
In a shallow bowl, whisk the egg white until frothy.
In another bowl, combine almond flour, smoked paprika, garlic powder, onion powder, salt, and pepper.
Dip the chicken breast into the egg white, then dredge in the almond flour mixture, pressing to adhere.
Place the chicken and yucca fries in the air fryer basket, spraying the chicken with the remaining avocado oil.
Air fry at 400°F for 12-15 minutes, flipping halfway through, until the chicken is cooked through and the yucca is golden.
Toast the bun and assemble the sandwich with the chicken, butter lettuce, and pickles, serving the yucca fries on the side.