Marinate chicken: Mix ¼ cup each oil and orange juice, 2 tablespoons each lime juice and lemon juice, ¼ cup onion, 1 tablespoon garlic and 1 teaspoon oregano in a large bowl. Season trimmed chicken thighs with ½ teaspoon salt and ½ teaspoon pepper. Add the chicken to the mojo marinade; cover and refrigerate for 2 hours.
Preheat oven to 400°F. Coat a large rimmed baking sheet with cooking spray.
Remove the chicken from the marinade and place on one half of the baking sheet. Strain the solids from the marinade; top the chicken with the onions and garlic; discard any remaining marinade.
Prepare vegetables: Toss cubed potatoes, 1 tablespoon oil, ½ teaspoon garlic powder, ¼ teaspoon each onion powder and chili powder and ⅛ teaspoon salt together in a clean large bowl. Add to the other half of the baking sheet; reserve the bowl. Roast the chicken and potatoes for 20 minutes.
Meanwhile, toss trimmed green beans in the reserved bowl with 1 tablespoon oil, ⅛ teaspoon pepper and the remaining ⅛ teaspoon salt. Stir the potatoes. Spread the green beans throughout the baking sheet; continue roasting until an instant-read thermometer inserted in the thickest part of the chicken registers 165°F and the potatoes and green beans are fork-tender, 15 to 20 minutes.
