Preheat your air fryer to 400°F (or preheat your oven to 425°F if air fryer is not available).
Cut the chicken breast into bite-sized pieces ensuring even cooking.
In a bowl, whisk the egg until well beaten. In a separate shallow dish, add the almond flour.
Dip each chicken piece first into the egg, then coat evenly with almond flour.
Place the coated chicken pieces in the air fryer basket in a single layer (or on a baking tray lined with parchment paper) and cook for 10-12 minutes, flipping halfway, until golden and crispy.
Meanwhile, in a small saucepan over medium heat, combine pineapple chunks, rice vinegar, honey, and soy sauce. Simmer for 3-4 minutes, stirring occasionally, until a slightly thickened sauce forms.
Remove the chicken from the air fryer (or oven) and transfer to a serving bowl.
Pour the sweet and sour sauce over the crispy chicken and toss gently to coat.
Serve immediately and enjoy the perfect balance of crispiness and tangy-sweet flavor.