In a shallow glass baking dish or in a large sealable bag, add the chicken Pour the lemon juice over, add the garlic, oregano, salt and pepper. Stir it all really well to combine. Pour the olive oil over top to seal it. Make sure that the chicken is submerged. Cover with lid or saran wrap and let marinade at least 30 minutes, preferably 8 hours / overnight.
Preheat the oven to 425ºF. On a rimmed baking sheet add the potatoes or cauliflower (or other veggies), bell peppers, and onion and toss with the remaining olive oil, lemon juice, oregano and a pinch of both salt and pepper. Toss well to combine. Arrange in an even layer.
Remove the marinade chicken, shake off excess marinade and arrange among the veggies. Transfer to the oven.
Roast for 40-45 minutes, tossing halfway through cooking until the chicken is cooked through, meat thermometer inserted in chicken registers 165-170°F and the potatoes or vegetables are golden. (sometimes I will give it a minute or two under the broiler to get things a little crispy)
Serve topped with lemon wedges, feta cheese, olives, fresh herbs, tzatziki, tahini, pickled red onions or however you'd like.
Notes
If you don't have time to marinate the chicken ahead, or even 30 minutes, just marinate it while you cut and prep the veggies, it will still be AMAZING! If using quicker cooking vegetables like zucchini or green beans, you may want to consider cooking the chicken for about 25 minutes first, alone, then taking it out and adding the seasoned vegetables to the pan and continue cooking together, so you don't have soggy / overcooked veggies. Alternatively you can also use a boneless, skinless chicken breast and cut it into tenders or strips and cook the entire tray for less time, 20-25 minutes.For AIP - opt for cauliflower, leave out red bell pepper, black pepper and skip on the feta cheese and tzatzikiFor Nightshade-free - Leave out the bell pepper and instead of white potatoes, opt for white sweet potato, cauliflower, etc