Preheat the oven to 400°F so it’s fully hot before cooking. Line a large sheet pan with parchment paper or foil. This prevents sticking and makes cleanup quick after cooking.
Pat the chicken breasts dry with paper towels to help them roast instead of steam. Place them on one side of the sheet pan, leaving space for vegetables.
Drizzle the chicken with olive oil and sprinkle lemon pepper seasoning, salt, and black pepper evenly. Rub gently so the seasoning coats the surface well.
In a bowl, toss halved baby potatoes and green beans with olive oil, garlic, and a pinch of salt. This ensures every piece gets flavor and roasts evenly.
Spread the vegetables around the chicken in a single layer. Add lemon slices on top and around the chicken to infuse flavor while roasting.
Place the sheet pan in the oven and roast for about 30 minutes. Flip vegetables halfway if desired. The chicken should reach 165°F internally.
Remove the pan from the oven and let everything rest for 5 minutes. This helps the chicken stay juicy and allows flavors to settle.