Combine maple syrup, Dijon mustard, garlic powder, and black pepper in a mixing bowl. Add thinly sliced chicken breasts and toss to coat completely. Cover bowl and refrigerate for at least 30 minutes, up to 2 hours.
Heat skillet over medium heat and cook bacon for 4-5 minutes per side until crispy. Transfer to paper towel-lined plate and reserve 1 tablespoon bacon drippings in skillet.
Increase heat to medium-high and add marinated chicken to skillet with reserved drippings in single layer. Cook without moving for 5-7 minutes until golden and caramelized. Flip and cook another 5-7 minutes until internal temperature reaches 165°F (74°C).
Remove chicken from skillet and let rest on clean plate for 3-4 minutes to allow juices to redistribute.
Slice slider buns in half and toast cut-side down in same skillet for 1-2 minutes until lightly golden.
Place one piece of chicken (about 1.5 ounces) on bottom bun, top with half slice of bacon and small handful of fresh arugula or spinach. Add top bun and serve warm.
Notes
Use pure maple syrup for best flavor. Thick-cut bacon provides better texture contrast.
Marinate chicken for minimum 30 minutes, up to 2 hours maximum for best results.
Store components separately in refrigerator for up to 3 days. Freeze assembled sliders wrapped tightly for up to 2 months.
Watch chicken carefully while cooking as maple syrup can caramelize quickly. Reduce heat if darkening too fast.