In a large bowl, whisk together all of the marinade ingredients (olive oil, balsamic vinegar, soy sauce, Dijon, lemon juice, brown sugar, salt, garlic powder, pepper, and paprika) until well combined.

Add the chicken thighs to the bowl and use tongs or clean hands to coat them thoroughly in the marinade. Make sure all sides of the chicken are well covered. Cover the bowl and refrigerate for at least 30 minutes, ideally 3 to 4 hours.

Preheat your grill to medium-high heat, aiming for around 400°F. Let the grill fully heat up before adding the chicken.

Place the marinated chicken thighs on the preheated grill. Cook for about 5 minutes on the first side with the lid closed. It's okay to take a peek at them to make sure they aren't burning, but for the most part, try to keep the lid closed. 

Flip the thighs and cook for another 5 minutes. Then begin checking the internal temperature of the thickest part of each thigh. You're looking for a final internal temperature of at least 170°F - 175°F.

Continue flipping and cooking the thighs as needed until they reach the proper temperature. Try to maintain a grill temp around 400°F throughout. If the grill gets too hot, lower the burner heat slightly. If it starts to cool down, turn the burners up. These adjustments help keep the thighs from over-charring on the outside before they're fully cooked.

Once cooked through, transfer the chicken thighs to a clean plate. Let them rest for about 10 minutes before serving to allow the juices to redistribute. Then, serve and enjoy!