Preheat the oven to 400°F and line a large rimmed baking sheet with parchment paper.
Place the asparagus, diced sweet potato, and cherry tomatoes on the sheet, then drizzle with olive oil and a pinch of sea salt and black pepper.
Roast the vegetables for 18 to 20 minutes, tossing halfway through, until the potatoes are tender and the asparagus is slightly charred.
While vegetables roast, season the chicken breast evenly on both sides with sea salt, black pepper, and dried oregano.
Heat the ghee in a heavy-bottomed skillet over medium-high heat until shimmering.
Place the chicken in the pan and sear for 6 minutes without moving it to develop a golden-brown crust.
Flip the chicken, add the minced garlic to the pan, and cook for another 5 to 6 minutes until the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest for 3 minutes before serving alongside the roasted vegetables.