Preheat oven to 400 degrees. Lightly grease a non stick baking sheet or line with parchment paper or aluminum foil.
In a medium skillet, toast the panko crumbs until lightly golden, stirring constantly. Remove from heat and set aside.
In a food processor, pulse the pretzels until coarsely ground and mix with the panko crumbs.
Wipe out the crumbs from the processor, and place oil, mustard, honey, water and vinegar and pulse until smooth. Season with salt and pepper to taste.
Pound the chicken with a mallet to even the thickness and season well with salt and pepper.
Set up a dredging station by pouring half of the dressing in a shallow bowl, put the flour in a large plate, and the pretzel mixture to a shallow bowl.
Dredge the chicken in the flour, then into the dressing and lastly coat in the pretzels. Place each chicken breast onto the baking sheet.
Bake 16-25 minutes or until cooked though. Serve with remaining honey mustard dressing.