Preheat the oven to 400°F (200°C).
In a bowl, toss the halved baby potatoes with 1 tablespoon olive oil, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper. Spread them evenly on a baking sheet.
Roast the potatoes in the preheated oven for 20-25 minutes, turning halfway through, until golden and tender.
While the potatoes roast, season both sides of the chicken breasts with 1 teaspoon kosher salt, 1/2 teaspoon black pepper, and 1 teaspoon garlic powder.
Heat 2 tablespoons olive oil in a large skillet over medium-high heat.
Add the chicken breasts to the skillet and cook for 5-6 minutes on one side without moving, until golden brown.
Flip the chicken breasts and cook for another 5-6 minutes, or until the internal temperature reaches 165°F (74°C). Remove chicken from the skillet and set aside to rest.
In the same skillet, reduce heat to medium and add 3 tablespoons unsalted butter.
Once the butter melts, add the minced garlic and cook for 1 minute until fragrant, stirring constantly to avoid burning.
Stir in 1 tablespoon fresh lemon juice and 1/2 teaspoon dried thyme. Remove from heat.
In a medium saucepan, bring 1/4 cup water to a boil. Add the trimmed green beans, cover, and steam for 4-5 minutes until tender-crisp.
Drain the green beans and season with a pinch of salt and pepper if desired.
To serve, place a chicken breast on each plate, spoon the garlic butter sauce over the chicken, and add a portion of roasted potatoes and steamed green beans on the side.