Cut each chicken breast in half horizontally so you have 4 cutlets ½ the thickness of the original breasts.
Place each cutlet between double plastic wrap sheets and pound lightly with a meat mallet until they are about ¼ to a ½" thick.
Mix flour, salt and pepper in one bowl. Whisk mustard, tarragon, lemon juice garlic and honey in a separate bowl.
Crush Honey Mustard Pretzel chunks so they make a coarse crumb similar to panko crumbs. You should have 2 cups of crumbs on a flat plate.
Dredge cutlets in flour dish, then spread each side with the mustard mixture. Dredge the cutlets in the crumbs. Cutlets should be evenly coated. Transfer each cutlet to a platter.
You can wrap and freeze the cutlets in a single layer at this point. You can also refrigerate for 30 minutes or more to help the breading adhere well but it is not mandatory.
When ready to cook, choose a setting that will give you 375°. Preheat the air fryer if necessary for your air fryer. (°See note below for pan frying.)
Spritz each cutlet with oil and position in single layer on your tray(s). Cook 8-10 minutes turning cutlets at mid point. If using more than one tray you may need to rotate the trays at mid point as well. Coating should be evenly browned and internal temperature should have reached 165°. Air fry in batches if necessary.
If cooking from frozen check internal temperature after 22 minutes following instructions above.
Serve with lemon wedges if desired.