Place pork between 2 sheets of heavy-duty plastic wrap, and flatten to 1/4-inch thickness, using a meat mallet or rolling pin.
Stir together mayonnaise and garlic powder. Dip pork in mayonnaise mixture; dredge in crushed pretzels.
Melt butter in a large nonstick skillet over medium heat. Add pork chops; sprinkle with sage. Cook 4 to 5 minutes on each side or until done.