In a medium bowl, whisk together red wine vinegar, olive oil, and lemon juice until well combined.
Add minced garlic, Italian seasoning, paprika, brown sugar, onion powder, salt, and pepper to the liquid mixture. Stir until all ingredients are thoroughly incorporated.
Place chicken in a large resealable plastic bag or shallow glass container.
Pour the marinade over the chicken, making sure all pieces are evenly coated.
Seal the bag or cover the container and refrigerate for at least 2 hours, though overnight marination will yield the most flavorful results.
When ready to cook, preheat your grill to medium-high heat (around 375-400°F).
Remove chicken from the marinade, allowing excess to drip off.
Grill chicken for 5-7 minutes per side (for breasts) or 6-8 minutes per side (for thighs), or until internal temperature reaches 165°F.
Let the grilled chicken rest for 5 minutes before serving to allow juices to redistribute.