Preheat your oven to 400°F (200°C) and line a small baking sheet with parchment paper.
Pierce the sweet potato with a fork and microwave for 5-7 minutes until soft, then scoop out the flesh and mash with a pinch of salt.
Trim the woody ends off the asparagus and toss them on the baking sheet with half of the olive oil and one minced garlic clove.
Season the chicken breast evenly with the dried oregano, sea salt, and black pepper.
Heat the remaining olive oil in a skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden and cooked through.
While the chicken cooks, roast the asparagus in the oven for 10-12 minutes until tender.
During the last minute of cooking the chicken, add the remaining minced garlic and lemon juice to the skillet, spooning the juices over the meat.
Plate the chicken alongside the roasted asparagus and mashed sweet potato, drizzling any remaining pan juices over the top.