Prepare the Chimichurri: In a bowl, combine the olive oil, lemon juice, parsley, garlic, chilies, oregano, salt, and pepper. Mix well and let sit for 5-10 minutes to allow the flavors to meld together. (If desired, you can prepare this step in advance and refrigerate the chimichurri for up to 24 hours.) Makes approximately 1 cup of chimichurri.
Marinate the Chicken: Season the chicken with a pinch of salt. Pour 4 tablespoons of chimichurri into a shallow dish and coat the chicken thoroughly. Let it marinate for 20 minutes (if time permits). Reserve the remaining chimichurri for serving.
Cook the Chicken: Heat a small amount of oil in a grill pan or skillet over medium-high heat. Cook the chicken for about 5-6 minutes per side, or until golden and cooked through. Once done, set the chicken aside to rest.
Serve: Spoon about 2-3 tablespoons of the remaining chimichurri over each chicken thigh or breast. Alternatively, serve the chimichurri in small dipping bowls for guests to add their own.