Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Trim the woody ends off the asparagus and place the spears on the prepared baking sheet.
In a small bowl, whisk together the smoked paprika, garlic powder, onion powder, cayenne pepper, sea salt, and black pepper.
Pat the chicken breast dry with a paper towel and rub the spice mixture evenly over both sides.
Drizzle half of the olive oil over the asparagus, tossing to coat evenly, and roast in the oven for 12 to 15 minutes.
Heat the remaining olive oil in a heavy-bottomed skillet or cast-iron pan over medium-high heat.
Add the chicken to the skillet and sear for 6 to 8 minutes per side until a dark crust forms and the internal temperature reaches 165°F.
Remove the chicken from the heat and squeeze the fresh lemon juice over both the chicken and the roasted asparagus before serving.