Marinate the chicken fingers for at least an hour in the buttermilk, or up to overnight. Somtimes I like to add a few splashes of hot sauce to the buttermilk, but it's not neceesary.
Drain the buttermilk & thoroughly coat the chicken fingers in the crushed crispy jalapenos. Set aside on a plate for 10-15 minutes for the breading to 'set' on the chicken.
Place the chicken fingers in your air fryer. Cook it in batches at 400 degrees for about 6 minutes on each side.
Alternatively, you can bake this in the oven. Place on a foil or parchment paper lined baking sheet and bake at 425 degrees for 18-20 minutes, turning halfway through.