In a large bowl, container, or sturdy zipper-top bag, combine the olive oil, garlic, lemon juice, vinegar, oregano, salt, and pepper. Stir to combine thoroughly, add the chicken, turn to coat well, then cover or seal, and refrigerate for 12 to 24 hours (or even up to 2 days!).
Preheat oven to 425 F. Line a rimmed baking sheet with aluminum foil and spray with nonstick cooking spray. Remove the chicken from the marinade and place on the baking sheet skin side up. Roast for about 40 minutes until cooked through, depending on the size of the thighs. Serve the roasted chicken hot, warm, or cold.
Notes
I like to mix the marinade right in the container or zip-top bag that I am going to marinate the chicken in.
The chicken should marinate for at least 12 hours, but I find the flavor is best if I leave it for at least 24 hours.
Don't marinate the chicken for more than 2 days, or the acids in the marinade may start to "cook" the chicken and make it mushy.