Preheat your oven to 400°F (200°C).
Butterfly the chicken breast by slicing horizontally almost all the way through and opening it like a book.
Place the sliced ham and Swiss cheese inside the chicken, then fold it closed and secure the edges with toothpicks.
In a shallow dish, whisk together the almond flour, sea salt, black pepper, and garlic powder.
Press the stuffed chicken breast into the almond flour mixture until it is lightly and evenly coated on all sides.
Heat the olive oil in an oven-safe skillet over medium-high heat and sear the chicken for 2 minutes per side until golden brown.
Transfer the skillet to the oven and bake for 12-15 minutes until the chicken reaches an internal temperature of 165°F.
While the chicken bakes, whisk together the Greek yogurt, Dijon mustard, and lemon juice in a small bowl until smooth.
Steam the asparagus spears for 4-5 minutes until they are bright green and tender-crisp.
Remove the toothpicks from the chicken and serve it drizzled with the Dijon sauce alongside the steamed asparagus.