Place the chicken tenders in a large bowl or zip-top bag. Pour the buttermilk over the chicken and sprinkle in half of the ranch seasoning packet. Mix well, cover, and refrigerate for at least 30 minutes (or up to overnight for even more flavor and tenderness).

Set up three shallow bowls. In the first, add the flour. In the second, beat the egg. In the third, mix the panko breadcrumbs with the remaining ranch seasoning. This setup makes the breading process quick and organized.

Remove the chicken from the buttermilk marinade, letting any excess drip off. Dredge each piece first in the flour, then dip it into the beaten egg, and finally coat it with the seasoned panko. Press gently to help the breadcrumbs stick well.

Preheat your air fryer to 400°F (200°C) for 3–5 minutes. Lightly spray the basket with cooking spray to prevent sticking.

Place the breaded chicken tenders in a single layer in the basket (work in batches if needed). Lightly spray the tops with cooking spray. Air fry for 10–12 minutes, flipping halfway through, until the coating is golden brown and the chicken is cooked through (internal temp of 165°F/74°C).