Mix the ground chicken with salt, black pepper, maple syrup, Dijon mustard, garlic powder, and paprika in a large mixing bowl until just combined.

Divide the mixture into four equal portions and shape each into a ¾-inch thick patty, making a thumb indent in the center.

Preheat the grill or skillet over medium heat for about 5 minutes, then grill the patties for 5-6 minutes on each side until golden brown and cooked through.

In the last minute of cooking, place a slice of Swiss cheese on each patty and cover to melt.

Toast the pretzel buns on the grill until golden and slightly crisped for about 1-2 minutes.

Assemble the burgers by placing the patty on the toasted bun, adding sauerkraut and crispy fried onions, and optionally drizzling with more maple syrup or Dijon mustard.