Add the chicken thighs to a large mixing bowl. Pour in the oil and toss to coat. Sprinkle the Italian seasoning, brown sugar, paprika, salt, and garlic powder over the chicken and toss until evenly coated.
Cover the bowl with plastic wrap and let marinate for 1 hour to overnight in the fridge. (see note)
Preheat the grill to 400 degrees F.
Cook the chicken on the hot grill for 6-7 minutes per side until cooked through (165 degrees F internal temp). Remove from the grill to a platter and serve warm.
Notes
The chicken can be cooked right away after it's seasoned. Marinating will help the flavors develop and is recommended. If you're cooking right away, preheat the grill before starting on the chicken.