Depending on how spicy and tart you like your sauce, play with the amount of lime juice and chili flakes.
Prepare the lamb marinade first. In a small bowl, combine olive oil, herbs, garlic and Dijon mustard. Place lamb chops on a sheet pan and season with salt and pepper. Spoon marinade over lamb chops making sure to coat both sides well. Let sit for at least 30 minutes or even overnight in the refrigerator. Be sure to remove from refrigerator at least 30-45 minutes before grilling.
Combine the fresh herbs, oregano and garlic in a food processor and process until finely chopped. Scrape the mixture into a bowl and stir in the olive oil, vinegar, lime juice, red pepper flakes and salt.
When grill is hot, cook lamb chops about 3-5 minutes per side for medium rare or until desired doneness. Let rest 5 minutes, then serve with Pistachio Herb Sauce. Serves 4.